Multi-beam random access procedure in handover execution

ABSTRACT

According to certain embodiments, a method by a wireless device is provided for beam-based random access. The method includes receiving, from a network node, a handover command, the handover command comprising at least one suitability threshold. Measurements of each of a plurality of beams detected by the wireless device are performed. The measurements of the plurality of beams are compared to the at least one suitability threshold. A particular beam is selected based on the comparison, and a random access procedure is initiated.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/224,629, filed Dec. 18, 2018, which is a continuation ofInternational Application No. PCT/IB2018/057512, filed Sep. 27, 2018,which claims the benefit of U.S. Application No. 62/564,799, filed Sep.28, 2017, the disclosures of which are fully incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates, in general, to wireless communicationsand, more particularly, to a multi-beam random access procedure inhandover execution.

BACKGROUND

An RRC_CONNECTED UE performs handovers in LTE when the UE needs tochange cells. That is summarized in 3GPP TS 36.300 and FIGS. 1A-1C asfollows:

-   -   0 The UE context within the source eNB contains information        regarding roaming and access restrictions which were provided        either at connection establishment or at the last TA update.    -   1 The source eNB configures the UE measurement procedures        according to the roaming and access restriction information and        e.g. the available multiple frequency band information.        Measurements provided by the source eNB may assist the function        controlling the UE's connection mobility.    -   2 A MEASUREMENT REPORT is triggered and sent to the eNB.    -   3 The source eNB makes decision based on MEASUREMENT REPORT and        RRM information to hand off the UE.    -   4 The source eNB issues a HANDOVER REQUEST message to the target        eNB passing necessary information to prepare the HO at the        target side (UE X2 signalling context reference at source eNB,        UE S1 EPC signalling context reference, target cell ID,        K_(eNB*), RRC context including the C-RNTI of the UE in the        source eNB, AS-configuration, E-RAB context and physical layer        ID of the source cell+short MAC-I for possible RLF recovery). UE        X2/UE S1 signalling references enable the target eNB to address        the source eNB and the EPC. The E-RAB context includes necessary        RNL and TNL addressing information, and QoS profiles of the        E-RABs.    -   5 Admission Control may be performed by the target eNB dependent        on the received E-RAB QoS information to increase the likelihood        of a successful HO, if the resources can be granted by target        eNB. The target eNB configures the required resources according        to the received E-RAB QoS information and reserves a C-RNTI and        optionally a RACH preamble. The AS-configuration to be used in        the target cell can either be specified independently (i.e. an        “establishment”) or as a delta compared to the AS-configuration        used in the source cell (i.e. a “reconfiguration”).    -   6 The target eNB prepares HO with L1/L2 and sends the HANDOVER        REQUEST ACKNOWLEDGE to the source eNB. The HANDOVER REQUEST        ACKNOWLEDGE message includes a transparent container to be sent        to the UE as an RRC message to perform the handover. The        container includes a new C-RNTI, target eNB security algorithm        identifiers for the selected security algorithms, may include a        dedicated RACH preamble, and possibly some other parameters i.e.        access parameters, SIBs, etc. The HANDOVER REQUEST ACKNOWLEDGE        message may also include RNL/TNL information for the forwarding        tunnels, if necessary.        As soon as the source eNB receives the HANDOVER REQUEST        ACKNOWLEDGE, or as soon as the transmission of the handover        command is initiated in the downlink, data forwarding may be        initiated.

As depicted in FIGS. 1A-1C, the method then continues to steps 7 to 16,which provide means to avoid data loss during HO, and are furtherdetailed in 10.1.2.1.2 and 10.1.2.3:

-   -   7 The target eNB generates the RRC message to perform the        handover, i.e. RRCConnectionReconfiguration message including        the mobilityControlInformation, to be sent by the source eNB        towards the UE. The source eNB performs the necessary integrity        protection and ciphering of the message. The UE receives the        RRCConnectionReconfiguration message with necessary parameters        (i.e. new C-RNTI, target eNB security algorithm identifiers, and        optionally dedicated RACH preamble, target eNB SIBS, etc.) and        is commanded by the source eNB to perform the HO. The UE does        not need to delay the handover execution for delivering the        HARQ/ARQ responses to source eNB.    -   8 The source eNB sends the SN STATUS TRANSFER message to the        target eNB to convey the uplink PDCP SN receiver status and the        downlink PDCP SN transmitter status of E-RABs for which PDCP        status preservation applies (i.e. for RLC AM). The uplink PDCP        SN receiver status includes at least the PDCP SN of the first        missing UL SDU and may include a bit map of the receive status        of the out of sequence UL SDUs that the UE needs to retransmit        in the target cell, if there are any such SDUs. The downlink        PDCP SN transmitter status indicates the next PDCP SN that the        target eNB shall assign to new SDUs, not having a PDCP SN yet.        The source eNB may omit sending this message if none of the        E-RABs of the UE shall be treated with PDCP status preservation.    -   9 After receiving the RRCConnectionReconfiguration message        including the mobilityControlInformation, UE performs        synchronisation to target eNB and accesses the target cell via        RACH, following a contention-free procedure if a dedicated RACH        preamble was indicated in the mobilityControlInformation, or        following a contention-based procedure if no dedicated preamble        was indicated. UE derives target eNB specific keys and        configures the selected security algorithms to be used in the        target cell.    -   10 The target eNB responds with UL allocation and timing        advance.    -   11 When the UE has successfully accessed the target cell, the UE        sends the RRCConnectionReconfigurationComplete message (C-RNTI)        to confirm the handover, along with an uplink Buffer Status        Report, whenever possible, to the target eNB to indicate that        the handover procedure is completed for the UE. The target eNB        verifies the C-RNTI sent in the        RRCConnectionReconfigurationComplete message. The target eNB can        now begin sending data to the UE.    -   12 The target eNB sends a PATH SWITCH REQUEST message to MME to        inform that the UE has changed cell.    -   13 The MME sends a MODIFY BEARER REQUEST message to the Serving        Gateway.    -   14 The Serving Gateway switches the downlink data path to the        target side. The Serving gateway sends one or more “end marker”        packets on the old path to the source eNB and then can release        any U-plane/TNL resources towards the source eNB.    -   15 The Serving Gateway sends a MODIFY BEARER RESPONSE message to        MME.    -   16 The MME confirms the PATH SWITCH REQUEST message with the        PATH SWITCH REQUEST ACKNOWLEDGE message.    -   17 By sending the UE CONTEXT RELEASE message, the target eNB        informs success of HO to source eNB and triggers the release of        resources by the source eNB. The target eNB sends this message        after the PATH SWITCH REQUEST ACKNOWLEDGE message is received        from the MME.    -   18 Upon reception of the UE CONTEXT RELEASE message, the source        eNB can release radio and C-plane related resources associated        to the UE context. Any ongoing data forwarding may continue.

When an X2 handover is used involving HeNBs and when the source HeNB isconnected to a HeNB GW, a UE CONTEXT RELEASE REQUEST message includingan explicit GW Context Release Indication is sent by the source HeNB, inorder to indicate that the HeNB GW may release of all the resourcesrelated to the UE context.

Concerning the handover execution and in particular the random accessprocedure, the 3GPP TS 38.331 specifications define the reception of anRRCCConnectionReconfiguranon including the mobilityControlInfo by the UEas the following:

If the RRCConnectionReconfiguration message includes themobilityControlInfo and the UE is able to comply with the configurationincluded in this message, the UE shall:

-   -   1> stop timer T310, if running;    -   1> stop timer T312, if running;    -   1> start timer T304 with the timer value set to t304, as        included in the mobilityControlInfo;    -   1> stop timer T370, if running;    -   1> if the carrierFreq is included:    -   2> consider the target PCell to be one on the frequency        indicated by the carrierFreq with a physical cell identity        indicated by the targetPhysCellId;    -   1> else:    -   2> consider the target PCell to be one on the frequency of the        source PCell with a physical cell identity indicated by the        targetPhysCellId;    -   1> start synchronising to the DL of the target PCell;    -   1> if MAC successfully completes the random access procedure; or    -   1> if MAC indicates the successful reception of a PDCCH        transmission addressed to C-RNTI:    -   2> stop timer T304;

The LTE random access procedure comes in two forms, allowing access tobe either contention-based (implying an inherent risk of collision) orcontention-free. In contention-based random access, a preamble sequenceis randomly chosen by the UE, which may result in more than one UEsimultaneously transmitting the same signature, leading to a need for asubsequent contention resolution process. For handovers, the eNodeB hasthe option of preventing contention occurring by allocating a dedicatedsignature to a UE (contention free).

FIG. 2 illustrates the contention-based procedure, which consists offour steps:

-   -   Preamble transmission;    -   Random access response;    -   Transmission of message 3 (MSG.3);    -   Contention resolution message.

With regard to preamble transmission in the first step of thecontention-based procedure, the UE selects one of the 64-Z PRACHcontention-based sequences (where Z is the Number allocation forcontention-free preambles allocated by the eNodeB). The set ofcontention-based signatures is further subdivided into two subgroups, sothat the choice of preamble can carry one bit of information relating tothe amount of transmission resource needed to transmit Message 3. Thebroadcast system information indicates which signatures are in each ofthe two subgroups (each subgroup corresponding to one value of the onebit of information), as well as the meaning of each subgroup. The UEselects a sequence from the subgroup corresponding to the size oftransmission resource needed for the appropriate RACH use case (some usecases require only a few bits to be transmitted in MSG.3, so choosingthe small message size avoids allocating unnecessary uplink resources).In selecting the appropriate resource size to indicate, the UE takesinto account the current downlink path-loss and the requiredtransmission power for MSG.3, in order to avoid being granted resourcesfor MSG.3 that would need a transmission power exceeding that which theUE's maximum power would allow. The transmission power required forMSG.3 message is calculated based on some parameters broadcast by theeNodeB, in order that the network has some flexibility to adapt themaximum size of MSG.3. The eNodeB can control the number of sequences ineach subgroup according to the observed loads in each group.

The initial preamble transmission power setting is based on an open-loopestimation with full compensation for the path-loss. This is designed toensure that the received power of the sequence is independent of thepath-loss. The UE estimates the path-loss by averaging measurements ofthe downlink Reference Signal Received Power (RSRP). The eNodeB may alsoconfigure an additional power offset, depending for example on thedesired received Signal to Interference plus Noise Ratio (SINR), themeasured uplink interference and noise level in the time-frequency slotsallocated to RACH preambles, and possibly also on the preamble format.

With regard to the Random Access Response (RAR) in the second step ofthe contention-based procedure, it is noted that the RAR conveys theidentity of the detected preamble (RAPID), a timing alignmentinstruction to synchronize subsequent uplink transmissions from the UE,an initial uplink resource grant for transmission of the Step 3 message,and an assignment of a temporary Cell Radio Network Temporary Identifier(C-RNTI) (which may or may not be made permanent as a result of the nextstep—md contention resolution). The RAR is also scrambled with theRA-RNTI when the RAR was detected and indicates the PRACH resource whenthe preamble was transmitted. The RAR message can also include a‘backoff indicator’ which the eNodeB can set to instruct the UE to backoff for a period of time before retrying a random access attempt. The UEexpects to receive the RAR within a time window, of which the start andend are configured by the eNodeB and broadcast as part of thecell-specific system information. If the UE does not receive a RARwithin the configured time window, it selects another sequence to betransmitted again. The minimum delay for the transmission of anotherpreamble after the end of the RAR window is 3 ms.

The eNodeB may configure preamble power ramping so that the transmissionpower for each transmitted preamble is increased by a fixed step. TheeNodeB can configure the steps in power ramping in terms of power andthe maximum number of attempts in total before declaring random accessfailure.

The Message 3 transmission in the third step of the contention-basedprocedure e is the first scheduled uplink transmission on the PUSCH andmakes use of HARQ. It is addressed to the temporary C-RNTI allocated inthe RAR and carries in the case of handovers the provided C-RNTI. Incase of a preamble collision having occurred at Step 1, the collidingUEs will receive the same temporary C-RNTI through the RAR and will alsocollide in the same uplink time-frequency resources when transmittingtheir L2/L3 message. This may result in such interference that nocolliding UE can be decoded, and the UEs restart the random accessprocedure after reaching the maximum number of HARQ retransmissions.However, if one UE is successfully decoded, the contention remainsunresolved for the other UEs. The following downlink message (in Step 4)allows a quick resolution of this contention.

With regard to contention resolution message in the fourth step of thecontention-based procedure, the contention resolution message uses HARQ.It is addressed to the C-RNTI (if indicated in the MSG.3 message) or tothe temporary C-RNTI, and, in the latter case, echoes the UE identitycontained in MSG.3. In case of a collision followed by successfuldecoding of the MSG.3, the HARQ feedback is transmitted only by the UEwhich detects its own UE identity (or C-RNTI); other UEs understandthere was a collision, transmit no HARQ feedback, and can quickly exitthe current random access procedure and start another one.

The aforementioned principles of handover, or network controlledmobility, are also expected to apply for the 5th generation of a radioaccess technology currently being under development in 3GPP. Manyagreements on the topic describe above have already been taken, some ofwhich are described below. The new technology and air interface solutionis often abbreviated with the term NR (New Radio).

The following agreements were taken in the following RAN1 meetings (RAN1#86bis) concerning the RACH procedure in connected mode and for NR:

-   -   When Tx/Rx reciprocity is available at gNB at least for multiple        beams operation, the following RACH procedure is considered for        at least UE in idle mode        -   Association between one or multiple occasions for DL            broadcast channel/signal and a subset of RACH resources is            informed to UE by broadcast system information or known to            UE            -   FFS: Signaling of “non-association”            -   Detailed design for RACH preamble should be further                studied        -   Based on the DL measurement and the corresponding            association, UE selects the subset of RACH resources            -   FFS: Tx beam selection for RACH preamble transmission        -   At gNB, the DL Tx beam for the UE can be obtained based on            the detected RACH preamble and would be also applied to            Message 2            -   UL grant in message 2 may indicate the transmission                timing of message 3    -   For the cases with and without Tx/Rx reciprocity, the common        random access procedure should be strived    -   When Tx/Rx reciprocity is not available, the following could be        further considered for at least UE in idle mode        -   Whether or how to report DL Tx beam to gNB, e.g.,            -   RACH preamble/resource            -   Msg. 3        -   Whether or how to indicate UL Tx beam to the UE, e.g.,            -   RAR    -   RAN1 is studying and some companies see potential benefits of a        simplified RACH procedure consisting of two main steps (Msg1 and        Msg2) for UEs    -   RAN1 has discussed the following:        -   The use of a UE identity in Msg 1        -   Msg 2: RA response that is addressed to the UE identity in            Msg 1        -   FFS on the definition and choice of the UE identity        -   FFS on the applicability scenarios of simplified RACH            procedure    -   RAN1 to send LS to RAN2    -   RAN1 is aware that RAN2 is also studying the RACH procedure and        RAN1 would like to inform RAN2 to take the above into        considerations and would like to request any feedback on UE        identities and associated procedure and also ask the        corresponding applicable scenarios    -   RACH resource        -   A time-frequency resource to send RACH preamble    -   Whether UE needs to transmit one or multiple/repeated preamble        within a subset of RACH resources can be informed by broadcast        system information        -   For example, to cover gNB RX beam sweeping in case of NO            Tx/Rx reciprocity at the gNB    -   NR supports multiple RACH preamble formats, including at least        -   RACH preamble format with longer preamble length        -   RACH preamble format with shorter preamble length        -   FFS how many signatures (e.g. number of RACH sequences,            payload size, etc.)    -   Multiple/repeated RACH preambles in a RACH resource is supported        -   FFS: How to support single-beam and/or multi-beam operation        -   FFS: Preamble could be the same or different    -   Numerology for RACH preamble can be different depending on        frequency ranges        -   FFS: How many numerologies will be supported per frequency            range    -   Numerology for RACH preamble can be different or the same from        that for the other UL data/control channels    -   In the evaluation for RACH preamble transmission and RACH        resource selection, companies report the following assumptions        -   Support of Rx beam sweeping at the base station        -   Support of coverage, e.g., the values defined in TR38.913

The following agreements were taken in the following RAN1 meetings (RAN1#87):

-   -   Following options can be further considered for the consecutive        multiple/repeated RACH preambles,        -   Option 1: CP is inserted at the beginning of the consecutive            multiple/repeated RACH sequences, CP/GT between RACH            sequences is omitted and GT is reserved at the end of the            consecutive multiple/repeated RACH sequences        -   Option 2: The same RACH sequences with CP is used and GT is            reserved at the end of the consecutive multiple/repeated            RACH sequences        -   Option 3: The same RACH sequences with CP/GT is used        -   Option 4: Different RACH sequences with CP is used and GT is            reserved at the end of the consecutive multiple/repeated            RACH sequences        -   Option 5: Different RACH sequences with CP/GT is used        -   For options 2 and 3, study further that the same RACH            sequences with and without GT can be further multiplied with            different orthogonal cover codes and transmitted.        -   For example, the consecutive multiple/repeated RACH            preambles would be used when Tx/Rx beam correspondence does            not hold at TRP        -   Other options are not precluded    -   For a single RACH preamble transmission, CP/GT are required        -   For example, the single RACH preamble would be used when            Tx/Rx beam correspondence held at both TRP or UE for            multi-beam operation    -   The maximum bandwidth for a RACH preamble transmission is not        wider than 5 MHz for a carrier frequency of below 6 GHz and not        wider than X MHz for a carrier frequency ranging from 6 GHz to        52.6 GHz        -   X will be down selected from 5, 10, and 20 MHz    -   At least, one reference numerology for RACH preamble is defined,        -   1.25×n kHz        -   15×n kHz    -   Integer value of n is FFS        -   Other values are not precluded    -   Based on the reference numerology for RACH preamble, multiple        RACH preambles with scalable numerologies are supported        depending on the carrier frequency    -   The following sequences can be considered for the evaluation        -   ZC sequence        -   m-sequence        -   Other sequences are not precluded    -   Companies are encouraged to provided their proposed sequence        length RAN1 has further agreed that the next steps should        include:    -   For down selection purpose, until the next meeting do evaluation        of the following RACH SCS alternatives at least considering        -   Robustness towards Doppler frequency, Beam sweeping latency,            Link budget, Cell size, RACH capacity, frequency offset    -   RACH SCS alternatives        -   SCS=[1.25 2.5 5 7.5 10 15 20 30 60 120 240] kHz    -   Note: in case RACH SCS=[15 30 60 120 240] there are two design        options:        -   use the same SCS as the subsequent UL data and control        -   use different SCS than the subsequent UL data and control    -   The following RACH preamble sequence types are considered        -   Zadoff-Chu        -   M-sequence        -   Zadoff-Chu with cover extension using M-sequence            Note that new designs are not precluded in the future.

It has been additionally agreed that:

-   -   For single/multi-beam operation,        -   For multiple/repeated RACH preamble transmissions, consider            only option 1, option 2 and option 4            -   Option 1: CP is inserted at the beginning of the                consecutive multiple/repeated RACH OFDM symbols, CP/GT                between RACH symbols is omitted and GT is reserved at                the end of the consecutive multiple/repeated RACH                symbols            -   Option 2/4: The same/different RACH sequences with CP is                used and GT is reserved at the end of the consecutive                multiple/repeated RACH sequences                -   Study:                -    Multiplexing with different orthogonal cover codes                -    Independent RACH sequences in a RACH preamble    -   For supporting various coverage and forward compatibility,        flexibility in the length of CP/GT and the number of repeated        RACH preambles and RACH symbols is supported    -   Note: specific use of these three options may depend on RACH        subcarrier spacing and TRP beam correspondence    -   NR defines that:        -   a random access preamble format consists of one or multiple            random access preamble(s),        -   a random access preamble consists of one preamble sequence            plus CP, and        -   one preamble sequence consists of one or multiple RACH OFDM            symbol(s)    -   UE transmits PRACH according to the configured random access        preamble format    -   For 4-step RACH procedure, a RACH transmission occasion is        defined as the time-frequency resource on which a PRACH message        1 is transmitted using the configured PRACH preamble format with        a single particular transmit beam.    -   For 4-step RACH procedure,        -   NR at least supports transmission of a single Msg.1 before            the end of a monitored RAR window        -   NR 4-step RACH procedure design should not preclude multiple            Msg.1 transmissions until the end of RAR window if need            arises    -   For NR RACH Msg. 1 retransmission at least for multi-beam        operation:    -   NR supports power ramping.        -   If the UE conducts beam switching, working assumption that            one of the alternatives below will be selected            (configurability between multiple alternatives may be            considered if clear benefit is shown):            -   Alt 1: the counter of power ramping is re-set.            -   Alt 2: the counter of power ramping remains unchanged.            -   Alt 3: the counter of power ramping keeps increasing.            -   Other alternatives or combinations of the above are not                precluded.        -   If UE doesn't change beam, the counter of power ramping            keeps increasing.        -   Note: UE may derive the uplink transmit power using the most            recent estimate of path loss.        -   The detail of power ramping step size is FFS.    -   Whether UE performs UL Beam switching during retransmissions is        up to UE implementation        -   Note: which beam UE switches to is up to UE implementation

The following agreements were also taken in the following RAN1 meetings(RAN1 #88):

-   -   Regarding multiple/repeated PRACH preamble formats, NR at least        supports option 1    -   RAN1 studies other options and consider option 1 as baseline for        comparison with other options        -   For RACH capacity enhancements,            -   Option 2 with/without OCC and/or option 4 with different                sequences can be considered                -   Note: for option 4, combination with different                    sequences can be studied                -   Note: for option 4, two-stage or multiple-stage UE                    detection can be studied for possible complexity                    reduction for PRACH detection        -   All options will consider beam switching time        -   FFS: Number of Preambles/Symbols, Length of CP/GT    -   The region for PRACH transmission should be aligned to the        boundary of uplink symbol/slot/subframe    -   Evaluate designs considering possibility to have larger number        of PRACH preamble sequences in a RACH transmission occasion than        in LTE    -   The following methods can be considered for evaluations:        -   Zadoff-Chu with cover extension using M-sequence        -   M-sequences        -   Zadoff-Chu sequence        -   Other methods are not precluded    -   Note that PAPR and false alarm of these different sequences        should also be evaluated    -   For PUSCH (re)transmissions corresponding to a RAR grant, study        following alternatives        -   Alt.1: The UL waveform(s) is fixed in the specifications            -   Note that UL waveform is either DFT-S-OFDM or CP-OFDM        -   Alt.2: The NW informs a UE whether to use DFT-S-OFDM or            CP-OFDM            -   FFS signalling method        -   Other alternatives are not precluded    -   For contention-free random access, the following options are        under evaluation        -   Option 1: Transmission of only a single Msg.1 before the end            of a monitored RAR window        -   Option 2: A UE can be configured to transmit multiple            simultaneous Msg.1            -   Note: multiple simultaneous Msg.1 transmissions use                different frequency resources and/or use the same                frequency resource with different preamble indices        -   Option 3: A UE can be configured to transmit multiple Msg.1            over multiple RACH transmission occasions in the time domain            before the end of a monitored RAR window    -   Following is baseline UE behaviour        -   UE assumes single RAR reception at a UE within a given RAR            window    -   NR random access design should not preclude UE reception of        multiple RAR within a given RAR window, if need arises    -   At least for the case without gNB Tx/Rx beam correspondence, gNB        can configure an association between DL signal/channel, and a        subset of RACH resources and/or a subset of preamble indices,        for determining Msg2 DL Tx beam.    -   Based on the DL measurement and the corresponding association,        UE selects the subset of RACH resources and/or the subset of        RACH preamble indices    -   A preamble index consists of preamble sequence index and OCC        index, if OCC is supported        -   Note: a subset of preambles can be indicated by OCC indices

The following agreements are from RAN1 #88bis:

-   -   NR RACH capacity shall be at least as high as in LTE        -   Such capacity is achieved by time/code/frequency            multiplexing for a given total amount of time/frequency            resources    -   Zadoff-Chu sequence is adopted in NR        -   FFS other sequence type and/or other methods in addition to            Zadoff-Chu sequence for the scenario, e.g., high speed and            large cells            -   FFS definition of large cell and high speed        -   FFS other sequence type and/or other methods for capacity            enhancements, e.g.:            -   At least in multi-beam and low speed scenario, regarding                multiple/repeated PRACH preamble formats, option 2 with                OCC across preambles                -   FFS: Option 2 with OCC across multiple/repeated                    preambles in high speed scenarios                -   PRACH preamble design composed with multiple                    different ZC sequences                -   Sinusoidal modulation on top of option 1    -   For Zadoff-Chu sequence type, the RAN1 specifications will        support two NR-PRACH sequence lengths (L)        -   L=839: SCS={1.25, 2.5, 5} KHz        -   Select one of            -   L=63/71: SCS={15, 30, 60, 120, 240} KHz            -   L=127/139: SCS={7.5, 15, 30, 60, 120} KHz        -   FFS: Supported sub-carrier spacings for each sequence length    -   FFS for other sequence types    -   Waveform for RACH message 3 can be DFT-S-OFDM or CP-OFDM.        Network signals directly or indirectly RACH message 3 waveform        to UE:        -   The network signals the waveform for RACH message 3 in the            remaining minimum SI as one bit    -   In NR, the RACH configuration provides at least:        -   RACH time/freq. information        -   RACH preamble format    -   Association between one or multiple occasions for SS block and a        subset of RACH resources and/or subset of preamble indices is        informed to UE by broadcast system information or known to UE or        FFS dedicated signalling        -   FFS gNB can configure an association between CSI-RS for L3            mobility and a subset of RACH resources and/or a subset of            preamble indices, for determining Msg2 DL Tx beam    -   NR supports indication of PRACH resource allocation for        non-contention based random access for a UE        -   FFS on how the PRACH resource is indicated for the UE        -   Note: PRACH resource refers to time/frequency/code resources            of the PRACH preamble    -   Update previous meeting as follows:    -   For NR RACH Msg. 1 retransmission at least for multi-beam        operation:    -   NR supports power ramping.        -   If the UE conducts beam switching, working assumption that            one of the alternatives below will be selected            (configurability between multiple alternatives may be            considered if clear benefit is shown):            -   Alt 1: the counter of power ramping is re-set.            -   Alt 2: the counter of power ramping remains unchanged.            -   Alt 3: the counter of power ramping keeps increasing.            -   Alt 4: as proposed on slide 4 and illustrated on slide 5                in R1-1706613            -   Other alternatives or combinations of the above are not                precluded.        -   If UE doesn't change beam, the counter of power ramping            keeps increasing.        -   Note: UE may derive the uplink transmit power using the most            recent estimate of path loss.        -   The detail of power ramping step size is FFS.    -   Whether UE performs UL Beam switching during retransmissions is        up to UE implementation        -   Note: which beam UE switches to is up to UE implementation

FIGS. 3 and 4 illustrates PRACH preamble formats for the sequence lengthof 839 as supported by NR and agreed to in RAN1 #89 (FFS on restrictedset and FFS other sequence(s) for large cell radius).

FIG. 5 illustrates WF on NR-RACH preamble formats for coverageenhancement ZTE, CMCC as discussed in R1-1709708. L is the sequencelength and Ts=1/(30720) ms. It is proposed to introduce a PRACH preambleformat that provides 3 dB MCL gain compared to LTE PRACH preamble format2. \

The following has been agreed to:

-   -   For L=839, NR at least supports subcarrier spacing of:        -   1.25 kHz        -   FFS: which one of 2.5 kHz or 5 kHz will be supported    -   For the shorter sequence length than L=839, NR supports sequence        length of L=127 or 139 with subcarrier spacing of {15, 30, 60,        120} kHz        -   Note: this is based on the assumption that 240 kHz            subcarrier spacing is not available for data/control        -   FFS: 7.5 kHz subcarrier spacing    -   Consider following new use cases for RACH design,        -   beam recovery requests        -   on demand SI requests    -   Study the following aspects:        -   requirements to satisfy above new use cases        -   impact on capacity        -   whether additional preamble format(s) is needed        -   impact on RACH procedure    -   If the UE conducts beam switching, the counter of power ramping        remains unchanged        -   FFS: UE behaviour after reaching the maximum power    -   RAN1 will definitely decide above FFS point    -   NR does not support to report UE capability of beam        correspondence during RACH procedure.        -   Note that UE capability of beam correspondence is reported            after RACH procedure    -   Random access (RA) configuration is included in remaining        minimum SI.    -   Continue discussion on        -   Whether all RA configuration information is transmitted in            all beams used for RMSI within a cell or not        -   Whether NW is mandated to use the same set of beams for RMSI            and SS block or not        -   Whether SS block and RMSI are spatial QCLed or not    -   RAN1 will study transmitting PRACH preambles in CONNECTED mode        in resources based on CSI-RS        -   FFS: use cases and configurations details based on CSI-RS    -   Confirm the working assumption on supporting format 3    -   For formats with L=839        -   Unrestricted sets are supported        -   For restricted sets            -   1.25 kHz: Restricted set A supported, Restricted set B                is FFS            -   5 kHz: Restricted set is supported with FFS if                Restricted set A, B or both are supported    -   For L=127/139 with option 1, formats with 1, 2, 4, 6, and 12        OFDM symbols are supported        -   Number of symbols can be adjusted if problems are identified    -   For 15 kHz subcarrier spacing,        -   Agree on following preamble formats A2, A3, B4        -   Working assumption on following preamble formats A0, A1, B0,            B1, B2, B3, C0, C1

Maximum Preamble # of Path profile Path profile Cell radius formatSequence TCP TSEQ TGP (Ts) (us) (meter) Use case A 0 1 144 2048 0 481.56 469 TA is already known or Very small cell 1 2 288 4096 0 96 3.13938 Small cell 2 4 576 8192 0 144 4.69 2,109 Normal cell 3 6 864 12288 0144 4.69 3,516 Normal cell B 0 1 144 2048 0 48 1.56 469 TA is alreadyknown or Very small cell 1 2 192 4096 96 96 3.13 469 Small cell 2 4 3608192 216 144 4.69 1,055 Normal cell 3 6 504 12288 360 144 4.69 1,758Normal cell 4 12 936 24576 792 144 4.69 3,867 Normal cell C 0 1 12402048 0 144 4.69 5300 Normal cell 1 2 1384 4096 0 144 4.69 6000 Normalcell

-   -   Note 1: Unit is Ts, where Ts=1/30.72 MHz        -   Note 2: PRACH preamble are aligned with OFDM symbol boundary            for data with same numerology        -   Note 3: Additional 16 Ts for every 0.5 ms should be included            in TCP when RACH preamble is transmitted across 0.5 ms            boundary or from 0.5 ms boundary        -   Note 4: For format A, GP can be defined within the last RACH            preamble among consecutively transmitted RACH preambles    -   For 30/60/120 kHz subcarrier spacing, preamble format can be        scaled according to subcarrier spacing.        -   Ts=1/(2*30720) ms for 30 kHz subcarrier spacing        -   Ts=1/(4*30720) ms for 60 kHz subcarrier spacing        -   Ts=1/(8*30720) ms for 120 kHz subcarrier spacing        -   Note that some of the formats may not be applicable to all            subcarrier spacings    -   The UE calculates the PRACH transmit power for the        retransmission at least based on the most recent estimate        pathloss and power ramping        -   The pathloss is measured at least on the SS block associated            with the PRACH resources/preamble subset    -   UE behaviour when reaching the maximum power        -   If the recalculated power is still at or above the Pc,max            -   The UE can transmit at maximum power even if it changes                its TX beam    -   All random access configuration information is broadcasted in        all beams used for RMSI within a cell        -   i.e, RMSI information is common for all beams    -   At least for handover case, a source cell can indicate in the        handover command,        -   Association between RACH resources and CSI-RS            configuration(s)        -   Association between RACH resources and SS blocks        -   A set of dedicated RACH resources (FFS:            time/frequency/sequence)        -   Note that above CSI-RS configuration is UE-specifically            configured    -   For contention free case, a UE can be configured to transmit        multiple Msg.1 over dedicated multiple RACH transmission        occasions in time domain before the end of a monitored RAR        window if the configuration of dedicated multiple RACH        transmission occasions in time domain is supported.        -   Note: The time resource used for ‘dedicated RACH in time            domain’ is different from the time resources of contention            based random access        -   Note: Multiple Msg1 can be transmitted with same or            different UE TX beams    -   For contention-based random access, an association between an SS        block in the SS burst set and a subset of RACH resources and/or        preamble indices is configured by a set of parameters in RMSI.        -   RAN1 strives to use the same set of parameters for different            cases, e.g. analog/hybrid/digital beamforming at gNB, level            of gNB beam correspondence, number of SS blocks, number of            frequency multiplexed PRACH resources, PRACH resource            density in time etc.        -   RAN1 strives to minimize the set of parameters.        -   FFS the set of parameters        -   FFS the number of SS blocks (if indicated in RMSI or MIB),            e.g. the actually transmitted SS blocks or the maximum            number (L).

The following has been agreed to in RAN1 #90:

-   -   For NR PRACH preamble L=839 with SCS=1.25 kHz, Ncs restricted        set type B is supported in addition to restricted set type A    -   For NR PRACH preamble L=839 with SCS 5 kHz, Ncs restricted set        type A and type B are supported    -   At least confirm the working assumption for preamble formats A1,

B1, B2, B3

-   -   Not define preamble format B0    -   Change TCP value from 192 to 216 and TGP value from 96 to 72 for        format B1    -   RACH preamble formats with L=839 is not supported in over-6 GHz        band, and is supported in below-6 GHz    -   For short sequence (L=127/139) based preamble formats, RACH        transmission at over-6 GHz band        -   supports 60 and 120 kHz subcarrier spacing, and        -   does not support 15 and 30 kHz subcarrier spacing    -   For short sequence (L=127/139) based preamble formats, RACH        transmission at below-6 GHz band        -   supports 15 and 30 kHz subcarrier spacing, and        -   does not support 60 and 120 kHz subcarrier spacing    -   Preamble formats for PRACH with short sequence length support        preamble formats A0, C0 and C2 in addition to the agreed formats        A1, A2, A3, B1, B2, B3 and B4, as illustrated in FIG. 6.    -   Same cyclic shift values as defined in LTE is applied for NR        PRACH preamble format 0 and 1.    -   FFS: Whether same cyclic shift values as defined in LTE can be        applied for NR PRACH preamble format 2 and 3, considering        parameters (e.g. delay spread, guard time, filter length, etc.)    -   It is up to UE implementation how to select the SS block and        corresponding PRACH resource for path-loss estimation and        (re)transmission based on SS blocks that satisfy threshold(s)        -   If UE does not detect a SS block that satisfy threshold(s),            it has the flexibility to select any SS block that allows UE            to meet the target received power of the RACH preamble with            its maximum transmit power        -   UE has a flexibility to select its RX beam to find the list            of SS blocks that satisfy the threshold(s)        -   FFS: whether threshold(s) for SS block selection is            configured or fixed in the spec        -   Counter of power ramping when UE changes its selected            SS-block in message 1 re-transmission is unchanged    -   UE computes pathloss based on “SS block transmit power” and SS        block RSRP    -   At least one “SS block transmit power” value is indicated to UE        in RMSI    -   FFS: whether and how to support multiple values    -   Note: different SS blocks in an SS burst set can be transmitted        with different power and/or with different Tx beamforming gain        at least as NW implementation    -   NR supports the total maximum number of transmissions, M (like        LTE), per carrier to indicate Random Access problem        -   M is NW configurable parameter    -   At least for initial access, RAR is carried in NR-PDSCH        scheduled by NR-PDCCH in CORESET configured in RACH        configuration        -   Note: CORESET configured in RACH configuration can be same            or different from CORESET configured in NR-PBCH    -   For single Msg1 RACH, the RAR window starts from the first        available CORESET after a fixed duration from the end of Msg1        transmission        -   The fixed duration is X T_s        -   X is the same for all RACH occasions        -   FFS: whether CORESET starting position is aligned with slot            boundary        -   FFS: the value of X        -   FFS: whether X is frequency range dependent    -   For a single Msg1 RACH from UE,        -   The size of a RAR window is the same for all RACH occasions            and is configured in RMSI        -   RAR window could accommodate processing time at gNB.            -   Maximum window size depends on worst case gNB delay                after Msg1 reception including processing delay,                scheduling delay, etc            -   Minimum window size depends on duration of Msg2 or                CORESET and scheduling delay    -   FFS: multiple Msg1 RACH case if supported    -   For initial access, either long sequence based preamble or short        sequence based preamble is configured in a RACH configuration    -   For contention-based NR 4-step RA procedure        -   SCS for Msg 1            -   configured in the RACH configuration        -   SCS for Msg 2            -   the same as the numerology of RMSI        -   SCS for Msg 3            -   configured in the RACH configuration separately from SCS                for Msg1        -   SCS for Msg 4            -   the same as in Msg.2    -   For contention-free RA procedure for handover, the SCS for Msg1        and the SCS for Msg2 are provided in the handover command    -   NR studies reporting of SS block index, e.g., strongest SS block        index, through Msg3 of contention based random access    -   NR studies reporting of multiple SS block indices through Msg1        of contention free random access procedure        -   e.g. network can assign multiple RACH transmission times and            RACH preambles to the UE. UE can convey one SS block index            by selecting a RACH transmission time and another SS block            index implicitly by selecting a RACH preamble    -   For format 2, same cyclic shift values as for format 0 and 1 are        used    -   Working assumption: L=139 is adopted as the sequence length for        the RACH Preamble Formats using the short sequence    -   Use one common table for cyclic shift (Ncs) values for short        sequence based PRACH formats for all SCS        -   Alt 1: The number of cyclic shift values is up to 16 values            represented by 4 bits        -   Alt 2: The number of cyclic shift values is up to 8 values            represented by 3 bits        -   Down-selection to be done this week. In addition, to come up            with the actual set of values    -   For format 3, use table below.    -   The underlined values are working assumption

Sequence length 839, SCS = 5 KHz Restricted RestrictedZeroCorrelationZoneConfig Unrestricted set type A set type B 0 0 36 36 113 57 57 2 26 72 60 3 33 81 63 4 38 89 65 5 41 94 68 6 49 103 71 7 55112 77 8 64 121 81 9 76 132 85 10 93 137 97 11 119 152 109 12 139 173122 13 209 195 137 14 279 216 — 15 419 237 —

-   -   Restricted set is not supported for NR PRACH preamble based on        short sequence length    -   Use one common table for cyclic shift (Ncs) values for short        sequence based PRACH formats for all SCS        -   The number of cyclic shift values is up to 16 values            represented by 4 bits, the following table is adopted

ZeroCorrelationZoneConfig Ncs values 0 0 1 2 2 4 3 6 4 8 5 10 6 12 7 138 15 9 17 10 19 11 23 12 27 13 34 14 46 15 69

-   -   NR defines the pattern of the slots that contain PRACH        resource(s) in to a larger time interval        -   FFS: time interval e.g 5/10/20 ms        -   FFS pattern        -   FFS numerology of the slot e.g SS block, UL/DL, Msg1 or            PUSCH    -   FFS: Within each slot        -   Alt1: RACH resources within a slot are consecutive        -   Alt2: RACH resources within a slot are not consecutive, e.g            to handle the case of CORESET monitoring, in the 2/4/7            symbols    -   At least for initial access,        -   The PDSCH for RAR is confined within NR UE minimum DL BW for            a given frequency band        -   The PDSCH for Msg4 is confined within NR UE minimum DL BW            for a given frequency band.        -   FFS: If PDSCH for RAR and Msg4 are confined within initial            active DL BWP.    -   Send an LS to RAN4 informing tone spacing and bandwidth of        different RACH preamble formats        -   Check if these RACH preamble formats are confined within            UE's minimum UL BW        -   Assigned to Dhiraj (Samsung)—R1-1716805, approved in            R1-1716814 with the following updates            -   The minimum uplink bandwidth needed for supporting this                PRACH preamble format is 1.25 MHz for 1.25 kHz SCS and 5                MHz for 5 kHz SCS.            -   Update the action to: RAN1 would like to ask RAN4 to                take the above information into account in their future                work, and to inform RAN1 if there are concerns over the                above information.    -   At least for initial access, the association between SS blocks        and RACH preamble indices and/or RACH resources is based on the        actually transmitted SS blocks indicated in RMSI    -   For RAR, X can be supported for the timing gap between the end        of MSg1 transmission and the starting position of the CORESET        for RAR        -   Value of X=ceiling(Δ/(symbol duration))*symbol duration,            where the symbol duration is based on the RAR numerology            -   Where Δ is to accommodate sufficient time for UE Tx-Rx                switching if needed (e.g., for TDD)                -   Note: UE Tx-Rx switching latency is up to RAN4    -   RMSI indicates only a single transmit power for SS blocks in        Rel-15    -   For initial access, threshold for SS block selection for RACH        resource association is configurable by network, where the        threshold is based on RSRP        -   FFS details, including ping-pong effect handling    -   NR supports at least slot based transmission of Msg2, Msg3 and        Msg4        -   Check if slot based scheduling can satisfy ITU requirement.            If not, investigate ways to meet ITU requirement, e.g.,            non-slot based transmission of Msg2, Msg3 and Msg4    -   Msg3 is scheduled by the uplink grant in RAR    -   Msg3 is transmitted after a minimum time gap from the end of        Msg2 over-the-air reception        -   gNB has the flexibility to schedule the transmission time of            Msg3 while ensuring the minimum time gap        -   FFS the minimum time gap w.r.t. UE processing capability

Based on the above described agreements, some conclusions may be made:

-   -   FFS Message 2 PDCCH/PDSCH is received by the UE assuming that        the PDCCH/PDSCH DMRS conveying message 2 is QCL'ed with the SS        block which the preamble/RACH occasion the UE sent is associated        to.    -   FFS Message 3 is transmitted by the UE assuming that the same Rx        beam as was used for PRACH preamble reception by gNB to which        the received RAR is associated to.    -   FFS If there is no beam reporting in RACH message 3, Message 4        PDCCH/PDSCH is received by the UE assuming that the PDCCH/PDSCH        DMRS conveying message 4 is QCL'ed with that of Msg 2.    -   FFS: If there is beam reporting in RACH message    -   3FFS: If and how beam reporting in RACH message 3 impacts        message 4 Tx QCL assumption

There currently exist certain challenge(s). For example, in NR, thereare some aspects that differ from LTE that impacts the UE behaviourduring handover (mobility) and corresponding random access in a targetcell or on a target beam.

By “target”, we here refer to the cell or beam that the UE attempts toconnect to. Typically this process of initiating a random access on a“target” cell/beam is initiated by, for example, a handover message thattells the UE to perform this mobility/handover. The “target” may also bea target beam or cell that the UE, at least in part, given restrictionsas described below, is selecting as the best candidate to use as the“target”.

In LTE, and as previously described in detail and here only summarized,the a UE in RRC_CONNECTED performs relevant measurements suitable formobility/handover decisions, sends those measurements to the networkbased on various measurement configurations received from the network,and the network then decides to hand over the UE to another cell. The“handover command” then tells the UE to access a particular cell usingthe random access procedure.

The added complexity causing that the LTE solution is not directlyapplicable to NR is that NR may include the concept of radio beams,beam-selection and beam handover. Beam support is intended to improveefficiency over the radio interface, and it is a necessary component ofthe NR technology to support higher frequencies.

According to current agreements in 3GPP, a cell may consist of multiplebeams. A random access attempt is initiated on a specific beam of acell. Therefore, a solution that would be most readily taken from theknown LTE solution, would include a “handover command” that would tellthe UE to perform the random access procedure on a particular beam. Thisis because, particularly for dedicated preambles (allocated by thenetwork and sent to the UE), the network must know which beam (or beams)that the UE may use for its random access preamble.

However, there is also a possibility that the UE may be told to access acell, but that the UE is allowed to select a beam among all beams withinthat cell. This would mean that the network controls the cell, but thatthe beam selection would be up to the UE, at least in part.

Under such conditions it would be important that the UE selects a goodbeam, and a problem could occur if the UE selects a beam that is notuseful or of suitable quality. This could result in suboptimalperformance of the UE, particularly if there are other beams that couldbe of better quality. Therefore, there is a need for a solution toimprove the beam selection process of the UE.

In each NR cell there can be multiple Synchronization Signal Blocks(SSB) set comprised of one or multiple SSBs that can be transmitted indifferent beams (or directions). For each of these directions there canbe some differences in the PRACH resource configuration. Hence, in NR,before initiating random access the UE shall perform beam selection (orSSB selection) within a cell to derive the PRACH resources that shouldbe used such as time/frequency resources and sequence(s).

In addition, it has been agreed that each cell can beamform additionalRSs (CSI-RS) in different beams and provide the UE with a mappingbetween PRACH resources and CSI-RS so that the beam selection can beperformed based on CSI-RS at least during handover.

Despite all the RAN1 agreements related to RACH procedure,retransmissions via power ramping/beam switching, the handling ofmeasurements for UL power estimation, there is no solution yet to how toensure that the UE selects a suitable and useful beam for random accessin a target cell.

SUMMARY

Certain aspects of the present disclosure and their embodiments mayprovide solutions to these or other challenges. According to certainembodiments, a handover command now includes a suitability threshold orthresholds for the purpose of ensuring that the beam-selected by thewireless device results in a beam selection that can guarantee adequateservice to the wireless device.

According to certain embodiments, a method by a wireless device isprovided for beam-based random access. The method includes receiving,from a network node, a handover command, the handover command comprisingat least one suitability threshold. The wireless device performsmeasurements of each of a plurality of beams detected by the wirelessdevice. The measurements of the plurality of beams are compared to theat least one suitability threshold. A particular beam of the pluralityof beams is selected based on the comparison and a random accessprocedure is imitated.

According to certain embodiments, a wireless device for beam-basedrandom access is provided. The wireless device includes memory operableto store instructions and processing circuitry operable to execute theinstructions to cause the wireless device to receive, from a networknode, a handover command, the handover command comprising at least onesuitability threshold. Measurements of each of a plurality of beamsdetected by the wireless device are performed. The measurements of theplurality of beams are compared to the at least one suitabilitythreshold. A particular beam of the plurality of beams is selected basedon the comparison and a random access procedure is imitated.

According to certain embodiments, a method by a target network node forinitiating beam-based random access with a wireless device is provided.The method includes transmitting, to a source network node connected tothe wireless device, a handover command. The handover command comprisesat least one suitability threshold. The at least one suitabilitythreshold comprises a minimum radio quality for use by the wirelessdevice in selecting a particular one of a plurality of beams to initiatehandover to the target network node. The method further includesreceiving, from the wireless device, a random access preamble.

According to certain embodiments, a target network node for initiatingbeam-based random access with a wireless device is provided. The targetnetwork node includes memory operable to store instructions andprocessing circuitry operable to execute the instructions to cause thetarget network node to transmit, to a source network node connected tothe wireless device, a handover command. The handover command comprisesat least one suitability threshold. The at least one suitabilitythreshold comprises a minimum radio quality for use by the wirelessdevice in selecting a particular one of a plurality of beams to initiatehandover to the target network node. A random access preamble isreceived from the wireless device.

According to certain embodiments, a method by a source network node forbeam-based random access is provided. The method includes receiving,from a target network node, a handover command comprising at least onesuitability threshold. The at least one suitability threshold comprisesa minimum radio quality for selecting a particular one of a plurality ofbeams by the wireless device to initiate handover with the targetnetwork node. The handover command is transmitted to a wireless deviceconnected to the source network node to initiate handover of thewireless device to the target network node.

According to certain embodiments, a source network node for initiatingbeam-based random access with a wireless device is provided. The sourcenetwork node includes memory operable to store instructions andprocessing circuitry operable to execute the instructions to cause thetarget network node to receive, from a target network node, a handovercommand comprising at least one suitability threshold. The at least onesuitability threshold comprises a minimum radio quality for selecting aparticular one of a plurality of beams by the wireless device toinitiate handover with the target network node. The handover command istransmitted to a wireless device connected to the source network node toinitiate handover of the wireless device to the target network node.

Certain embodiments may provide one or more of the following technicaladvantage(s). For example, one technical advantage may be that certainembodiments provide a solution enabling a UE to perform contention-freerandom access or contention-based random access as long as T304 timer isnot expired. Accordingly, another technical advantage may be that the UEavoids failure.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed embodiments and theirfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIGS. 1A, 1B, and 1C illustrate a procedure by which an RRC_CONNECTED UEperforms handovers in LTE when needing to change cells;

FIG. 2 illustrates a contention-based procedure;

FIG. 3 illustrates PRACH preamble formats for the sequence length of 839as supported by NR;

FIG. 4 illustrates additional PRACH preamble formats for the sequencelength of 839 as supported by NR;

FIG. 5 illustrates WF on NR-RACH preamble formats for coverageenhancement

FIG. 6 illustrates preamble formats for PRACH with short sequencelength;

FIGS. 7A and 7B illustrate an example method for beam-based randomaccess, according to certain embodiments;

FIG. 8 illustrates an exemplary network for beam-based random access,according to certain embodiments;

FIG. 9 illustrate an example network node for beam-based random access,according to certain embodiments;

FIG. 10 illustrates an example wireless device for beam-based randomaccess, according to certain embodiments;

FIG. 11 illustrates an example UE for beam-based random access,according to certain embodiments;

FIG. 12 illustrates a virtualization environment in which functionsimplemented by some embodiments may be virtualized, according to certainembodiments;

FIG. 13 illustrates a telecommunication network connected via anintermediate network to a host computer, according to certainembodiments;

FIG. 14 illustrates a host computer communicating via a base stationwith a user equipment over a partially wireless connection, according tocertain embodiments;

FIG. 15 illustrates a method implemented in a communication system,according to certain embodiments;

FIG. 16 illustrates another method implemented in a communicationsystem, according to certain embodiments;

FIG. 17 illustrates another method implemented in a communicationsystem, according to certain embodiments;

FIG. 18 illustrates another method implemented in a communicationsystem, according to certain embodiments;

FIG. 19 illustrates another method by a wireless device for beam-basedrandom access, according to certain embodiments;

FIG. 20 illustrates an example virtual computing device for beam-basedrandom access, according to certain embodiments;

FIG. 21 illustrates a method by a target network node for imitatingbeam-based random access with a wireless device, according to certainembodiments;

FIG. 22 illustrates another example virtual computing device forbeam-based random access, according to certain embodiments;

FIG. 23 illustrates a method by a source network node for beam-basedrandom access with a wireless device, according to certain embodiments;and

FIG. 24 illustrates another example virtual computing device forbeam-based random access, according to certain embodiments.

DETAILED DESCRIPTION

Generally, all terms used herein are to be interpreted according totheir ordinary meaning in the relevant technical field, unless adifferent meaning is clearly given and/or is implied from the context inwhich it is used. All references to a/an/the element, apparatus,component, means, step, etc. are to be interpreted openly as referringto at least one instance of the element, apparatus, component, means,step, etc., unless explicitly stated otherwise. The steps of any methodsdisclosed herein do not have to be performed in the exact orderdisclosed, unless a step is explicitly described as following orpreceding another step and/or where it is implicit that a step mustfollow or precede another step. Any feature of any of the embodimentsdisclosed herein may be applied to any other embodiment, whereverappropriate. Likewise, any advantage of any of the embodiments may applyto any other embodiments, and vice versa. Other objectives, features andadvantages of the enclosed embodiments will be apparent from thefollowing description.

Some of the embodiments contemplated herein will now be described morefully with reference to the accompanying drawings. Other embodiments,however, are contained within the scope of the subject matter disclosedherein, the disclosed subject matter should not be construed as limitedto only the embodiments set forth herein; rather, these embodiments areprovided by way of example to convey the scope of the subject matter tothose skilled in the art.

According to certain embodiments, there is disclosed a solution wherethe network sends a handover command to a user equipment (UE). Thehandover command is sent from a node, such as an NR base-station (gNB).This node is hereafter called the Target or Target node. The handovercommand is sent to the UE via the Source base station. The Source basestation is the station that the UE is currently connected to. The Sourcebase station can be an NR base-station or e.g. an LTE base-station. Thehandover command is sent through the Source, and may be transparent tothe Source base-station, so that the handover command is received by theUE from the Target via the Source. Thus, the UE receives the handovercommand. The hand-over command may also be understood to mean aSecondary Cell Group (SCG) change or SCG addition command indual-connectivity context (in some embodiments this could be aninter-RAT node e.g., NR is the target that prepares the command).

According to certain embodiments, the handover command includes asuitability parameter or suitability parameters, such as a threshold orthresholds. In a particular embodiment, the suitability threshold may bea RACH or PRACH suitability threshold. The purpose of the suitabilitythreshold(s) is to ensure that the beam-selection by the UE results in abeam selection which can guarantee adequate service to the UE.

In an particular embodiment, for example, a Target network node, whichmay include a gNB, sends a handover command to the wireless device,which may include a UE. The handover command includes at least onesuitability threshold. The suitability threshold tells the UE that theUE shall only select a beam if the beam quality is over a certain radioquality threshold. In a particular embodiment, the quality threshold maybe expressed, for example, as a minimum reference signal power orquality, such as RSRP or RSRQ. Additionally or alternatively, thethreshold or thresholds may be associated with different ReferenceSignals. For example, NR includes both SS/PBCH and CSI-RS referencesignals, as will be further described below.

According to certain embodiments, the UE then performs correspondingmeasurements on relevant reference signals available on the beams orobtains an estimate of the beam quality such as, for example, based onprevious measurements or extrapolation, and compares the measured orestimated value (in e.g. RSRP, RSRQ) to the received threshold. If themeasured power/quality is greater than the threshold, then the UEclassifies the beam as being “suitable”, and the UE can now select thebeam for a random access attempt. This solution ensures that the UE doesnot select a beam within the cell that is not suitable or best for theUE.

In a particular embodiment, different suitability thresholds may bedefined for Contention Based Random Access (CBRA) and Contention FreeRandom Access (CFRA). In CBRA, the UE selects the RA resource and thepreamble transmission can therefore be subject to collision. In CFRA,the UE receives the particular time/frequency resources and beam orbeams that are available for CFRA, including a preamble or preambles,resulting in that no collision takes place.

There is a benefit of having different suitability thresholds for CFRAand CBRA, since it may be acceptable to have lower quality requirementsfor CFRA as there are other benefits, such as collision avoidance andlatency, with CFRA compared to CBRA. Having the possibility to definedifferent threshold for CFRA and CBRA enables the network to configurethe UE with two different suitability thresholds in the same handovercommand message, one for CFRA and another for CBRA. Upon handoverexecution, the UE can prioritize beams with CFRA resources by comparingthe quality of beams with CFRA with the provided suitability thresholdassociated to CFRA e.g. threshold-CFRA and, if no beams with CFRA aresuitable (i.e. with quality above the threshold-CFRA), the UE comparesthe remaining beams with threshold-CBRA and, if at least one isavailable the UE can perform contention CFRA. In that case the networkcan include two RACH configurations in the handover command, one relatedto CFRA and another related to CBRA e.g. as part of themobilityControlInfo IE or equivalent IE, in the case of SCG addition orSCG change.

In another embodiment, different suitability thresholds may be definedfor different reference signals, such as SS/PBCH and CSI-RS. Thus, in aparticular embodiment, the UE may receive a handover command thatincludes at least two thresholds for beam suitability evaluation.

In yet another particular embodiment, a suitability threshold may beassociated with a particular beam or with a particular reference signal.In still another particular embodiment, a suitability threshold may beassociated with a type of random access, such as CBRA or CFRA. Inparticular, since CFRA is likely to be associated with synchronizationsignal block (SSB) based handover, but CFRA can be associated witheither SSB based handover or channel-state information-reference signal(CSI-RS) based handover, it is appears beneficial to associate differentthresholds for the CBRA and CFRA, since the corresponding referencesignals may be transmitted differently, e.g. with different power. Therecan also be a combination of conditions, e.g., two thresholds areprovided: one for SSB based CFRA and another for SSB based CBRA, one forCSI-RS based CFRA and another for SSB based CBRA, one for CSI-RS basedCFRA and another for CSI-RS based CBRA.

According to certain embodiments, the UE may be allowed to send multipleRACH preambles before the RAR window expires. Hence, in that sense,there could be multiple thresholds for the 2nd best beam, 3rd bestbeams, . . . , Nth best beam for that particular purpose.

In some embodiments, there could also be multiple suitability thresholdsto be used depending whether that is preamble transmission or a preamblere-transmission. For example, a more relaxed threshold could be set forre-transmissions.

According to certain embodiments, there may also be differentsuitability thresholds for UL preamble retransmissions if the UEperforms UL Tx beamforming. In the case the UE is capable of UL Txtransmission, as there is a lower chance to create interference in alarger area, a more relaxed threshold could be used compared to the casethe UE does not use UL Tx beamforming.

There could also be different thresholds for retransmissions in the casethe UE uses power ramping without beam selection compared to beamselection with initial power. In the case of power ramping, for example,the threshold could also be relaxed. During the beam selection for RACHpreamble retransmissions the UE may select the same beam or a differentbeam. Hence, there can be different thresholds for these two differentcases.

Thus, in some embodiments, the target may send multiple suitabilitythresholds that may apply to different beams in a cell. This disclosurealso contemplates about the possibility of having several candidatecells in the handover command including one or multiplethresholds/parameters to govern the suitability of the beams within thecells.

It should be noted that the determination of whether a beam within acell is “suitable” according to the description above is only onedetermination that the UE may have to perform in relation to beamselection and random access resource selection. The aforementionedsolution must work together with other aspects necessary for beam andrandom access resource selection, including e.g. to prioritize amongbeams detected by the UE, and interworking with dedicated preambles thatmay be available on specific beams, only. Thus, finding that a beam issuitable is one step in the process of selecting a good or the best beamfor a random access attempt, but the solution should also work togetherwith other selection steps, as will be described below.

For example, in one solution, the UE must first evaluate the suitabilitythresholds related to CFRA on the relevant beam or beams. Then, if thebeam or beams are found not to be suitable, the UE proceeds byevaluating other beams bases on additional thresholds, for CBRA. Theevaluation of CFRA and CBRA may be associated with different referencesymbols.

There is also a need to define recovery solutions in case no beamfulfils the criteria of suitability, as defined by the parameters andthe corresponding evaluation performed by the UE. This will be furtherelaborated below.

According to certain embodiments, a network solution is defined forcoordinating the measurement reporting thresholds with the thresholds ofsuitability evaluation. This is because the measurement configurationthat the UE receives from the network that is used for evaluatingwhether a measurement report is to be sent, is typically configured fora carrier frequency, not per-cell.

Thus, a criterion for sending measurement reports to the Sourcetypically applies to multiple cells on a carrier frequency, wherein thecells on the carrier frequency are controlled by multiple base-stations.Currently, the Target is responsible for setting the suitabilitythresholds described above. Thus, it could occur that a Source basestation configures a UE to report neighbour cell measurements at asignal strength/quality level that is below the suitability threshold ofthe Target. This problem can be alleviated by, for example, certainsolutions described herein.

For example, in a particular embodiment, a Source may communicate themeasurement configuration to the Target (i.e. sends a message), so thatthe Target can set its Suitability thresholds so that no conflict occursbetween the reporting and the Suitability criteria configured by thetarget, when the target issues the handover command. By this solution,the target can ensure that its suitability thresholds that are sent tothe UE are sensible in the sense that the UE is likely to find asuitable beam when obeying the handover command.

According to other embodiments, the Target network node may communicateits suitability thresholds to neighbouring nodes (that are likely to actas Sources), using a message or messages. The neighbour nodes can thenset the measurement criteria when configuring the UE to reportmeasurements so that unnecessary measurement reports are avoided. Oralternatively, or including, such that a UE is not handed over to atarget that will set the suitability threshold or thresholds above thesignal quality or power levels that the UE is currently reporting to aSource. Thereby, unnecessary handover attempts can be avoided.

In the described embodiments, a message can refer to an RRC signallingmessage. In the case of RRC, an example is the handover command, in factan RRCConnectionReconfiguration with a mobilityControlInfo IE containthe RACH configuration of the target cell. However, that can be anymessage from any protocol level triggering the UE to perform randomaccess. In fact, it is highly likely that that the “handover command”message may have a different name in NR. The relevance though is thatthis “handover command” message is used to command, from the network tothe UE, the UE to access another cell or beam, wherein the accessing,but the UE, includes synchronizing to the other cell or beam using arandom access procedure. The random access attempt can be performedusing e.g. a dedicated preamble and/or random access resource (aspreviously described) or a randomly selected preamble and resource. Therandom access attempt may be performed on a PRACH channel. The handovercommand will include the aforementioned threshold or thresholds, asdescribed above.

According to certain embodiments, beam can refer to an SS/PBCH Block(SSB) that is beamformed and that can be measured by the UE e.g. UE cancompute SS-RSRP. Each SSB encodes a PCI and, SSBs associated to the sameNR cell transmits the same PCI. In addition, each SSB has its own SSBindex, which can be derived from the demodulation Reference Signal(DMRS) of PBCH, a time index (e.g. encoded in PBCH) or a combination ofthese (as the combination can make a unique SS/BCH block identifier).The term beam can also refer to a CSI-RS resource that is beamformed andcan be measured by the UE e.g. UE can compute CSI-RSRP, CSI-RSRQ,CSI-SINR. Each CSI-RS may have a PCI associated to it so the UE can usefor synchronization before it measures a CSI-RS resource.

According to certain embodiments, measurement results(s) per beam can beper beam RSRP, per beam RSRQ, per beam SINR. In the case SS/PBCH blockis used as the reference signal (RS) type for beam level measurement,SS-RSRP, SS-RSRQ, SS-SINR are used. In the case CSI-RS is used as thereference signal (RS) type for beam level measurement, CSI-RSRP,CSI-RSRQ, CSI-SINR are used. It should be noted that measurements, andcorresponding suitability thresholds, can be defined for differentreference signal types.

According to certain embodiments, a suitable beam is the one whosemeasurement results fulfil a condition based on an absolute threshold,which can either be configurable or defined in the standard. Forexample, a beam b(i) is suitable if RSRP of b(i)>absolute threshold.Other measurement quantities could also be used as the criteria e.g. ifRSRQ of b(i)>absolute threshold, if SINR of b(i)>absolute threshold.Combinations of measurement quantities could also be used as thecriteria e.g. if RSRQ of b(i)>absolute threshold 1 AND if SINR ofb(i)>SINR absolute threshold 2 then b(i) is suitable, if RSRP ofb(i)>absolute threshold 1 AND if SINR of b(i)>absolute threshold 2 thenb(i) is suitable; if RSRQ of b(i)>absolute threshold 1 AND if RSRP ofb(i)>absolute threshold 2 then b(i) is suitable; if RSRQ ofb(i)>absolute threshold 1 AND if RSRP of b(i)>absolute threshold 2 ANDif SINR of b(i)>absolute threshold 3 then b(i) is suitable. It should beunderstood that the above mathematical relations using greater than (>)are merely examples and other operators including, but not limited to,less than (<), less than or equal (1, greater than or equal (?), equal(=), not equal can also be considered. These operators can also becombined with logical operators, including but not limited to, AND, OR,XOR, NOT to form new mathematical relations.

According to certain embodiments, target cell may be a cell differentfrom any serving cell the UE is being indicated to synchronize to duringa handover. The target cell could also be the same as any serving celle.g. when the UE performs random access or equivalent procedure tore-gain synch with its serving cell before radio link failure istriggered, such as in beam selection during beam recovery (although eventhat procedure could also be configured to be performed in a differentcell).

According to certain embodiments, synchronizing may be understoodbroadly, where e.g. the random access procedure can be used forsynchronizing between the UE and the base-station. This RA in LTE and NRmay include e.g. time-synchronization with time-alignment of the UEtransmissions to fit a slotted structure. It may also include indicatingfrom the UE to the network by transmitting a preamble in a RA procedurethat the UE has found a cell or beam and is ready to send and/orreceive.

According to certain embodiments, a UE obtains an estimate of the beamquality per beam index associated to the target cell. This estimate maybe obtained for all beams or only for a subset of beams. This can bedone, for example, according to the following alternatives

1. The UE can use previously performed measurement results per beamindex.

2. The UE can update the measurement results per beam index for thetarget cell.

-   -   i. Measurement update can be filtered measurement results, i.e.,        taking into account previously performed measurements. The        filter coefficient could either be defined or configured.        Depending on the filter coefficients, only the latest sample        matter i.e. filter without memory.    -   ii. Measurement update can occur in a faster periodicity        compared to the one the UE uses for the configured event        measurement evaluation considering that it may require more up        to date measurement results to perform a proper random access        procedure. The usage of different sampling periodicities can be        configured and/or adjusted based on different criteria such as        the detection of UE movement, UE speed or speed state, etc. In        some embodiments/scenarios the sampling rate may depend on the        physical properties of the radio channel (e.g., carrier        frequency and SCS).

3. The UE can decide between using previously performed measurementresults per beam index or perform an update of measurements based ondifferent criteria. One criteria could be that the latest measurementwas performed more than X ms before the message was received by the UE,which can indicate that these are outdated and preamble transmissioncould fail due to a wrong estimation of initial UL power transmission.If the message is received before the X ms, the measurement could beconsidered valid and the UE does not have to perform any update in themeasurements. Another criterion could be based on UE speed, which couldindicate that changes are more likely to occur if the UE speed ishigher. There can be a speed state defined or speed thresholds. Anothercriterion could be based on UE movements such as rotation. If a rotationis detected between the time the UE perform the latest measurements, theUE should perform measurement updates before selecting the beam to startrandom access. There can be a combination of these abovementionedcriteria.

In addition to measuring the beam quality, the UE may also use othermethods to estimate it. For example, the UE may extrapolate the beamquality for a particular beam based on measurements performed on anotherbeam.

The outcome of that phase can be, for example, the following:

-   -   [Beam(1): RSRP-1, Beam(2): RSRP2, . . . , Beam(K): RSRP(K)],        and/or    -   [Beam(1): RSRQ-1, Beam(2): RSRQ2, . . . , Beam(K): RSRQ(K)]        and/or    -   [Beam(1): SINR-1, Beam(2): SINR-2, . . . , Beam(K): SINR(K)] for        K suitable beam indexes where all of them have their measurement        quantity, RSRP in this example, above the threshold.

FIGS. 7A and 7B illustrate an example method for beam-based randomaccess, according to certain embodiments. At step 100, the UE receives amessage from the network containing zero or more Dedicated RACHresources associated to beams associated to the target cell the UEshould synchronize to and perform random access. The message may alsocontain common RACH resources.

At step 102, upon receiving the message, the UE starts the HandoverFailure timer (e.g. T304 like timer).

At step 104, the UE estimates the beam quality per beam index associatedto the target cell as explained above (e.g. by steps 1-3). For example,the UE may:

-   -   use previous estimates for some or all of the beams    -   use previously performed measurement results per beam index    -   update the measurement results per beam index for the target        cell.

At steps 106 and 108, the UE identifies, based on the previous step,whether any of the beams that have been configured with associateddedicated RACH resources are suitable. For example, the UE may evaluatewhether any of the beams with dedicated RACH configuration is suitableat step 106, and then determine if at least one suitable beam was foundat step 108. The suitability of a beam may be associated with a beam orRS-specific threshold. The evaluation of whether the beam is suitablecan be associated with a beam and/or reference signal type suitabilitythreshold. Thus, the evaluation may depend on whether the CFRA isassociated with a particular reference signal.

If at least one suitable beam with associated dedicated RACH resourcesis found to be suitable at step 108, the method continues to FIG. 7Balong the “A” path, and the UE selects one of the beams based ondifferent criteria and perform random access with the associatedresources, at step 110. For example, the UE may send an UL preamble andstart the configured RAR time window, in a particular embodiment.

Examples of criteria that may be used to select one of multiple suitablebeams may include:

-   -   One criterion could be that the UE selects the suitable beam        with strongest measurement quantity;    -   Another criterion could be that the UE selects the suitable beam        whose time domain RACH resources occur first, to prioritize        latency.    -   Another criterion could be that the UE selects the suitable beam        that has higher stability i.e. based on radio condition        statistics the UE figures out that the radio conditions for that        beam has not changed dramatically within a period of time.

If multiple beams are suitable with dedicated RACH resources, the UE mayselect any based on the abovementioned criteria. However, an alternativecan be that the UE sends multiple preambles for any subset of dedicatedRACH resources associated to the suitable beams.

Returning to step 108 illustrated in FIG. 7A, if none of the beams withassociated dedicated RACH resource are suitable, the method continues toFIG. 7B along the “B” path and the UE selects a suitable beam withcommon RACH resources fulfilling the different criteria at step 112.

At steps 114 or 116, the UE determines if a RAR scrambled with the UEsRA-RNTI and containing the UE's RAPID is received before the RAR windowexpires. In either case, if the UE receives the RAR within the RARwindow the procedure is considered successful at step 118, and the UEprepares the handover complete message to be transmitted to the targetcell.

If at steps 114 or 116 it is determined that the UE does not receive aRAR before the RAR time window expires, the UE shall either performspower ramping on the same beam or switching to a new beam using the samepower at step 120. The UE may also re-estimate the beam quality per beamindex.

If after re-evaluating the quality at step 120, there is at least onesuitable beam with dedicated RACH, the UE shall select the onefulfilling the different criteria defined. Else, if after re-evaluatingthe quality there are no suitable beam with dedicated RACH, the UE mayverify whether T304 is still running. If T304 has not expired, the UEshall select a suitable beam with common RACH resources fulfilling thedifferent criteria defined in and goes to step 118. Else, if T304 hasexpired, the UE declares random access failure and inform upper layers.

According to certain embodiments, the UE receives a RAR scrambled withthe UEs RA-RNTI and containing a Back-off indicator (BI) in step 118 or120. In that case, the UE may either back-off as instructed by the BIand continue the procedure from step 120 or update the beam qualityestimation e.g. using the method (1)-(3) above. If the UE can select adifferent suitable beam than the one used for the previous attempt, theUE may use this new beam and continue the procedure from step 120without doing back-off.

In that embodiment, the back-off indicator may contain different typesof information that will drive different UE actions:

-   -   The BI may be valid for the specific beam the UE has selected        and tried to access RACH associated to it. In that case the UE        can try to select any other suitable beam for preamble        re-transmission without the need to wait. If the only suitable        beam is the one whose BI is associated to, then the UE waits the        backoff time before accessing gain.    -   The BI may contain back-off time values for multiple beams i.e.        the UE is only allowed to perform preamble re-transmissions        before the back-off time the resources associated to suitable        beams not in the provided BI. And, if multiple beams are        indicated, the UE shall selected any with dedicated resource        that is suitable and is not present in the BI.

According to certain embodiments, the UE receives a message from thenetwork containing Dedicated RACH resources associated to all beamsassociated to the target cell the UE should synchronize to and performrandom access. Upon receiving that message, the UE shall perform steps102 to 120 in FIGS. 7A-7B, with following modifications:

-   -   If as an outcome of the (n+1)-th beam re-selection the UE        re-selects the same beam as in the n-th (re-)selection, the UE        performs power ramping as that indicates that the same direction        was still be best one, although the UL power was not sufficient.        Alternatively, the UE can perform instead or in addition to        power ramping, UL beam switching to transmit the preamble e.g.        in the case the UE has the possibility to transmit narrower UL        beams compared to wider DL Tx beams that remained unchanged.    -   If as an outcome of the (n+1)-th beam re-selection the UE        re-selects another beam compared to the n-th (re-)selection, as        an indication that another direction should be tried, the UE        starts to perform random access with initial power level        estimation and/or continues its power ramping levels.    -   The UE continues the procedure from step 120, i.e. UE starts RA        using the selected beam with the associated RACH resource        (time/frequency/sequence) that was provided and starts the timer        associated to the configured random access response (RAR) time        window.

According to certain embodiments, the UE receives the RAR scrambled withthe UEs RA-RNTI and containing the UEs RAPID, it stops the timerassociated to the configured random access response (RAR) time windowand considers random access procedure successful. In cases when thetimer associated to the configured random access response (RAR) timewindow timer expires or the UE receives a RAR with back-off, the UE canre-attempt the error handling procedure until

-   -   the counter of transmitted preambles is equal to a previously        configured value. Said counter is incremented every time the UE        performs a transmission, independently whether:        -   the UE has performed power ramping without UL beam switching            and without DL beam switching or        -   the UE has performed power ramping with UL beam switching            and without DL beam switching,        -   the UE has performed power ramping with UL beam switching            and with DL beam switching,        -   the UE has performed power ramping without UL beam switching            and with DL beam switching,        -   the UE has not performed power ramping, but performed UL            beam switching with DL beam switching;        -   the UE has not performed power ramping, but performed UL            beam switching without DL beam switching,        -   the UE has not performed power ramping, but performed DL            beam switching without UL beam switching,    -   the timer T304 expires;

In this embodiment, if all beams have dedicated resources configured forthat UE, these resources are valid as long as T304 is running. Thetarget node can maintain that timer and, when it expires, the targetnode can either convert these in common RACH resources or allocate asdedicated RACH resource to other UEs.

In another particular embodiment, the UE may receive a message from thenetwork that may contain only common RACH resources associated to allbeams associated to the target cell that the UE should synchronize toand perform random access. Upon receiving that message, the UE shallperform the same actions defined for the case where the UE receives onlydedicated RACH resources, as described in the first embodiment with theexception that the RACH resources used in step 120 are common resources.If that message does not contain the common RACH the UE shall use the apreviously acquired common RACH configuration such as the one definedfor the source cell.

In the previous embodiments it was described that the UE receives amessage that triggers the UE to perform random access e.g. handovercommand message. However, the remaining steps after the triggering ofrandom access are also applicable in the case beam selection does nothave to be triggered by a message, such as beam recovery, triggered bythe detection of beam failure. In that case the UE may be configuredwith dedicated and common UL channel resources via a message, althoughthe beam selection procedure itself is triggered by other criteria.

Also, although we talked about random access during handover as the mainprocedure involved in beam selection, the procedures are also valid forbeam recovery in the sense that the UE also needs to perform beamselection, may also be configured with UL channel resources (like PRACHresources) and also wait for a response before a failure is declared.

FIG. 8 illustrates a wireless network, according to certain embodiments.Although the subject matter described herein may be implemented in anyappropriate type of system using any suitable components, theembodiments disclosed herein are described in relation to a wirelessnetwork, such as the example wireless network illustrated in FIG. 8. Forsimplicity, the wireless network of FIG. 8 only depicts network 406,network nodes 460 and 460 b, and WDs 410, 410 b, and 410 c. In practice,a wireless network may further include any additional elements suitableto support communication between wireless devices or between a wirelessdevice and another communication device, such as a landline telephone, aservice provider, or any other network node or end device. Of theillustrated components, network node 460 and wireless device (WD) 410are depicted with additional detail. The wireless network may providecommunication and other types of services to one or more wirelessdevices to facilitate the wireless devices' access to and/or use of theservices provided by, or via, the wireless network.

The wireless network may comprise and/or interface with any type ofcommunication, telecommunication, data, cellular, and/or radio networkor other similar type of system. In some embodiments, the wirelessnetwork may be configured to operate according to specific standards orother types of predefined rules or procedures. Thus, particularembodiments of the wireless network may implement communicationstandards, such as Global System for Mobile Communications (GSM),Universal Mobile Telecommunications System (UMTS), Long Term Evolution(LTE), and/or other suitable 2G, 3G, 4G, or 5G standards; wireless localarea network (WLAN) standards, such as the IEEE 802.11 standards; and/orany other appropriate wireless communication standard, such as theWorldwide Interoperability for Microwave Access (WiMax), Bluetooth,Z-Wave and/or ZigBee standards.

Network 406 may comprise one or more backhaul networks, core networks,IP networks, public switched telephone networks (PSTNs), packet datanetworks, optical networks, wide-area networks (WANs), local areanetworks (LANs), wireless local area networks (WLANs), wired networks,wireless networks, metropolitan area networks, and other networks toenable communication between devices.

Network node 460 and WD 410 comprise various components described inmore detail below. These components work together in order to providenetwork node and/or wireless device functionality, such as providingwireless connections in a wireless network. In different embodiments,the wireless network may comprise any number of wired or wirelessnetworks, network nodes, base stations, controllers, wireless devices,relay stations, and/or any other components or systems that mayfacilitate or participate in the communication of data and/or signalswhether via wired or wireless connections.

FIG. 9 illustrates a network node, according to certain embodiments. Asused herein, network node refers to equipment capable, configured,arranged and/or operable to communicate directly or indirectly with awireless device and/or with other network nodes or equipment in thewireless network to enable and/or provide wireless access to thewireless device and/or to perform other functions (e.g., administration)in the wireless network. Examples of network nodes include, but are notlimited to, access points (APs) (e.g., radio access points), basestations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs(eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based onthe amount of coverage they provide (or, stated differently, theirtransmit power level) and may then also be referred to as femto basestations, pico base stations, micro base stations, or macro basestations. A base station may be a relay node or a relay donor nodecontrolling a relay. A network node may also include one or more (orall) parts of a distributed radio base station such as centralizeddigital units and/or remote radio units (RRUs), sometimes referred to asRemote Radio Heads (RRHs). Such remote radio units may or may not beintegrated with an antenna as an antenna integrated radio. Parts of adistributed radio base station may also be referred to as nodes in adistributed antenna system (DAS). Yet further examples of network nodesinclude multi-standard radio (MSR) equipment such as MSR BSs, networkcontrollers such as radio network controllers (RNCs) or base stationcontrollers (BSCs), base transceiver stations (BTSs), transmissionpoints, transmission nodes, multi-cell/multicast coordination entities(MCEs), core network nodes (e.g., MSCs, MMEs), O&M nodes, OSS nodes, SONnodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As anotherexample, a network node may be a virtual network node as described inmore detail below. More generally, however, network nodes may representany suitable device (or group of devices) capable, configured, arranged,and/or operable to enable and/or provide a wireless device with accessto the wireless network or to provide some service to a wireless devicethat has accessed the wireless network.

In FIG. 9, network node 460 includes processing circuitry 470, devicereadable medium 480, interface 490, auxiliary equipment 484, powersource 486, power circuitry 487, and antenna 462. Although network node460 illustrated in the example wireless network of FIG. 8 may representa device that includes the illustrated combination of hardwarecomponents, other embodiments may comprise network nodes with differentcombinations of components. It is to be understood that a network nodecomprises any suitable combination of hardware and/or software needed toperform the tasks, features, functions and methods disclosed herein.Moreover, while the components of network node 460 are depicted assingle boxes located within a larger box, or nested within multipleboxes, in practice, a network node may comprise multiple differentphysical components that make up a single illustrated component (e.g.,device readable medium 480 may comprise multiple separate hard drives aswell as multiple RAM modules).

Similarly, network node 460 may be composed of multiple physicallyseparate components (e.g., a NodeB component and a RNC component, or aBTS component and a BSC component, etc.), which may each have their ownrespective components. In certain scenarios in which network node 460comprises multiple separate components (e.g., BTS and BSC components),one or more of the separate components may be shared among severalnetwork nodes. For example, a single RNC may control multiple NodeB's.In such a scenario, each unique NodeB and RNC pair, may in someinstances be considered a single separate network node. In someembodiments, network node 460 may be configured to support multipleradio access technologies (RATs). In such embodiments, some componentsmay be duplicated (e.g., separate device readable medium 480 for thedifferent RATs) and some components may be reused (e.g., the sameantenna 462 may be shared by the RATs). Network node 460 may alsoinclude multiple sets of the various illustrated components fordifferent wireless technologies integrated into network node 460, suchas, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wirelesstechnologies. These wireless technologies may be integrated into thesame or different chip or set of chips and other components withinnetwork node 460.

Processing circuitry 470 is configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being provided by a network node. These operationsperformed by processing circuitry 470 may include processing informationobtained by processing circuitry 470 by, for example, converting theobtained information into other information, comparing the obtainedinformation or converted information to information stored in thenetwork node, and/or performing one or more operations based on theobtained information or converted information, and as a result of saidprocessing making a determination.

Processing circuitry 470 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software and/or encoded logicoperable to provide, either alone or in conjunction with other networknode 460 components, such as device readable medium 480, network node460 functionality. For example, processing circuitry 470 may executeinstructions stored in device readable medium 480 or in memory withinprocessing circuitry 470. Such functionality may include providing anyof the various wireless features, functions, or benefits discussedherein. In some embodiments, processing circuitry 470 may include asystem on a chip (SOC).

In some embodiments, processing circuitry 470 may include one or more ofradio frequency (RF) transceiver circuitry 472 and baseband processingcircuitry 474. In some embodiments, radio frequency (RF) transceivercircuitry 472 and baseband processing circuitry 474 may be on separatechips (or sets of chips), boards, or units, such as radio units anddigital units. In alternative embodiments, part or all of RF transceivercircuitry 472 and baseband processing circuitry 474 may be on the samechip or set of chips, boards, or units

In certain embodiments, some or all of the functionality describedherein as being provided by a network node, base station, eNB or othersuch network device may be performed by processing circuitry 470executing instructions stored on device readable medium 480 or memorywithin processing circuitry 470. In alternative embodiments, some or allof the functionality may be provided by processing circuitry 470 withoutexecuting instructions stored on a separate or discrete device readablemedium, such as in a hard-wired manner. In any of those embodiments,whether executing instructions stored on a device readable storagemedium or not, processing circuitry 470 can be configured to perform thedescribed functionality. The benefits provided by such functionality arenot limited to processing circuitry 470 alone or to other components ofnetwork node 460, but are enjoyed by network node 460 as a whole, and/orby end users and the wireless network generally.

Device readable medium 480 may comprise any form of volatile ornon-volatile computer readable memory including, without limitation,persistent storage, solid-state memory, remotely mounted memory,magnetic media, optical media, random access memory (RAM), read-onlymemory (ROM), mass storage media (for example, a hard disk), removablestorage media (for example, a flash drive, a Compact Disk (CD) or aDigital Video Disk (DVD)), and/or any other volatile or non-volatile,non-transitory device readable and/or computer-executable memory devicesthat store information, data, and/or instructions that may be used byprocessing circuitry 470. Device readable medium 480 may store anysuitable instructions, data or information, including a computerprogram, software, an application including one or more of logic, rules,code, tables, etc. and/or other instructions capable of being executedby processing circuitry 470 and, utilized by network node 460. Devicereadable medium 480 may be used to store any calculations made byprocessing circuitry 470 and/or any data received via interface 490. Insome embodiments, processing circuitry 470 and device readable medium480 may be considered to be integrated.

Interface 490 is used in the wired or wireless communication ofsignalling and/or data between network node 460, network 406, and/or WDs410. As illustrated, interface 490 comprises port(s)/terminal(s) 494 tosend and receive data, for example to and from network 406 over a wiredconnection. Interface 490 also includes radio front end circuitry 492that may be coupled to, or in certain embodiments a part of, antenna462. Radio front end circuitry 492 comprises filters 498 and amplifiers496. Radio front end circuitry 492 may be connected to antenna 462 andprocessing circuitry 470. Radio front end circuitry may be configured tocondition signals communicated between antenna 462 and processingcircuitry 470. Radio front end circuitry 492 may receive digital datathat is to be sent out to other network nodes or WDs via a wirelessconnection. Radio front end circuitry 492 may convert the digital datainto a radio signal having the appropriate channel and bandwidthparameters using a combination of filters 498 and/or amplifiers 496. Theradio signal may then be transmitted via antenna 462. Similarly, whenreceiving data, antenna 462 may collect radio signals which are thenconverted into digital data by radio front end circuitry 492. Thedigital data may be passed to processing circuitry 470. In otherembodiments, the interface may comprise different components and/ordifferent combinations of components.

In certain alternative embodiments, network node 460 may not includeseparate radio front end circuitry 492, instead, processing circuitry470 may comprise radio front end circuitry and may be connected toantenna 462 without separate radio front end circuitry 492. Similarly,in some embodiments, all or some of RF transceiver circuitry 472 may beconsidered a part of interface 490. In still other embodiments,interface 490 may include one or more ports or terminals 494, radiofront end circuitry 492, and RF transceiver circuitry 472, as part of aradio unit (not shown), and interface 490 may communicate with basebandprocessing circuitry 474, which is part of a digital unit (not shown).

Antenna 462 may include one or more antennas, or antenna arrays,configured to send and/or receive wireless signals. Antenna 462 may becoupled to radio front end circuitry 490 and may be any type of antennacapable of transmitting and receiving data and/or signals wirelessly. Insome embodiments, antenna 462 may comprise one or more omni-directional,sector or panel antennas operable to transmit/receive radio signalsbetween, for example, 2 GHz and 66 GHz. An omni-directional antenna maybe used to transmit/receive radio signals in any direction, a sectorantenna may be used to transmit/receive radio signals from deviceswithin a particular area, and a panel antenna may be a line of sightantenna used to transmit/receive radio signals in a relatively straightline. In some instances, the use of more than one antenna may bereferred to as MIMO. In certain embodiments, antenna 462 may be separatefrom network node 460 and may be connectable to network node 460 throughan interface or port.

Antenna 462, interface 490, and/or processing circuitry 470 may beconfigured to perform any receiving operations and/or certain obtainingoperations described herein as being performed by a network node. Anyinformation, data and/or signals may be received from a wireless device,another network node and/or any other network equipment. Similarly,antenna 462, interface 490, and/or processing circuitry 470 may beconfigured to perform any transmitting operations described herein asbeing performed by a network node. Any information, data and/or signalsmay be transmitted to a wireless device, another network node and/or anyother network equipment.

Power circuitry 487 may comprise, or be coupled to, power managementcircuitry and is configured to supply the components of network node 460with power for performing the functionality described herein. Powercircuitry 487 may receive power from power source 486. Power source 486and/or power circuitry 487 may be configured to provide power to thevarious components of network node 460 in a form suitable for therespective components (e.g., at a voltage and current level needed foreach respective component). Power source 486 may either be included in,or external to, power circuitry 487 and/or network node 460. Forexample, network node 460 may be connectable to an external power source(e.g., an electricity outlet) via an input circuitry or interface suchas an electrical cable, whereby the external power source supplies powerto power circuitry 487. As a further example, power source 486 maycomprise a source of power in the form of a battery or battery packwhich is connected to, or integrated in, power circuitry 487. Thebattery may provide backup power should the external power source fail.Other types of power sources, such as photovoltaic devices, may also beused.

Alternative embodiments of network node 460 may include additionalcomponents beyond those shown in FIG. 9 that may be responsible forproviding certain aspects of the network node's functionality, includingany of the functionality described herein and/or any functionalitynecessary to support the subject matter described herein. For example,network node 460 may include user interface equipment to allow input ofinformation into network node 460 and to allow output of informationfrom network node 460. This may allow a user to perform diagnostic,maintenance, repair, and other administrative functions for network node460.

FIG. 10 illustrates a wireless device, according to certain embodiments.As used herein, wireless device (WD) refers to a device capable,configured, arranged and/or operable to communicate wirelessly withnetwork nodes and/or other wireless devices. Unless otherwise noted, theterm WD may be used interchangeably herein with user equipment (UE).Communicating wirelessly may involve transmitting and/or receivingwireless signals using electromagnetic waves, radio waves, infraredwaves, and/or other types of signals suitable for conveying informationthrough air. In some embodiments, a WD may be configured to transmitand/or receive information without direct human interaction. Forinstance, a WD may be designed to transmit information to a network on apredetermined schedule, when triggered by an internal or external event,or in response to requests from the network. Examples of a WD include,but are not limited to, a smart phone, a mobile phone, a cell phone, avoice over IP (VoIP) phone, a wireless local loop phone, a desktopcomputer, a personal digital assistant (PDA), a wireless cameras, agaming console or device, a music storage device, a playback appliance,a wearable terminal device, a wireless endpoint, a mobile station, atablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mountedequipment (LME), a smart device, a wireless customer-premise equipment(CPE). a vehicle-mounted wireless terminal device, etc. A WD may supportdevice-to-device (D2D) communication, for example by implementing a 3GPPstandard for sidelink communication, vehicle-to-vehicle (V2V),vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may inthis case be referred to as a D2D communication device. As yet anotherspecific example, in an Internet of Things (IoT) scenario, a WD mayrepresent a machine or other device that performs monitoring and/ormeasurements, and transmits the results of such monitoring and/ormeasurements to another WD and/or a network node. The WD may in thiscase be a machine-to-machine (M2M) device, which may in a 3GPP contextbe referred to as an MTC device. As one particular example, the WD maybe a UE implementing the 3GPP narrow band internet of things (NB-IoT)standard. Particular examples of such machines or devices are sensors,metering devices such as power meters, industrial machinery, or home orpersonal appliances (e.g. refrigerators, televisions, etc.) personalwearables (e.g., watches, fitness trackers, etc.). In other scenarios, aWD may represent a vehicle or other equipment that is capable ofmonitoring and/or reporting on its operational status or other functionsassociated with its operation. A WD as described above may represent theendpoint of a wireless connection, in which case the device may bereferred to as a wireless terminal. Furthermore, a WD as described abovemay be mobile, in which case it may also be referred to as a mobiledevice or a mobile terminal.

As illustrated, wireless device 410 includes antenna 411, interface 414,processing circuitry 420, device readable medium 430, user interfaceequipment 432, auxiliary equipment 434, power source 436 and powercircuitry 437. WD 410 may include multiple sets of one or more of theillustrated components for different wireless technologies supported byWD 410, such as, for example, GSM, WCDMA, LTE, NR, WiFi, WiMAX, orBluetooth wireless technologies, just to mention a few. These wirelesstechnologies may be integrated into the same or different chips or setof chips as other components within WD 410.

Antenna 411 may include one or more antennas or antenna arrays,configured to send and/or receive wireless signals, and is connected tointerface 414. In certain alternative embodiments, antenna 411 may beseparate from WD 410 and be connectable to WD 410 through an interfaceor port. Antenna 411, interface 414, and/or processing circuitry 420 maybe configured to perform any receiving or transmitting operationsdescribed herein as being performed by a WD. Any information, dataand/or signals may be received from a network node and/or another WD. Insome embodiments, radio front end circuitry and/or antenna 411 may beconsidered an interface.

As illustrated, interface 414 comprises radio front end circuitry 412and antenna 411. Radio front end circuitry 412 comprise one or morefilters 418 and amplifiers 416. Radio front end circuitry 414 isconnected to antenna 411 and processing circuitry 420, and is configuredto condition signals communicated between antenna 411 and processingcircuitry 420. Radio front end circuitry 412 may be coupled to or a partof antenna 411. In some embodiments, WD 410 may not include separateradio front end circuitry 412; rather, processing circuitry 420 maycomprise radio front end circuitry and may be connected to antenna 411.Similarly, in some embodiments, some or all of RF transceiver circuitry422 may be considered a part of interface 414. Radio front end circuitry412 may receive digital data that is to be sent out to other networknodes or WDs via a wireless connection. Radio front end circuitry 412may convert the digital data into a radio signal having the appropriatechannel and bandwidth parameters using a combination of filters 418and/or amplifiers 416. The radio signal may then be transmitted viaantenna 411. Similarly, when receiving data, antenna 411 may collectradio signals which are then converted into digital data by radio frontend circuitry 412. The digital data may be passed to processingcircuitry 420. In other embodiments, the interface may comprisedifferent components and/or different combinations of components.

Processing circuitry 420 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software, and/or encoded logicoperable to provide, either alone or in conjunction with other WD 410components, such as device readable medium 430, WD 410 functionality.Such functionality may include providing any of the various wirelessfeatures or benefits discussed herein. For example, processing circuitry420 may execute instructions stored in device readable medium 430 or inmemory within processing circuitry 420 to provide the functionalitydisclosed herein.

As illustrated, processing circuitry 420 includes one or more of RFtransceiver circuitry 422, baseband processing circuitry 424, andapplication processing circuitry 426. In other embodiments, theprocessing circuitry may comprise different components and/or differentcombinations of components. In certain embodiments processing circuitry420 of WD 410 may comprise a SOC. In some embodiments, RF transceivercircuitry 422, baseband processing circuitry 424, and applicationprocessing circuitry 426 may be on separate chips or sets of chips. Inalternative embodiments, part or all of baseband processing circuitry424 and application processing circuitry 426 may be combined into onechip or set of chips, and RF transceiver circuitry 422 may be on aseparate chip or set of chips. In still alternative embodiments, part orall of RF transceiver circuitry 422 and baseband processing circuitry424 may be on the same chip or set of chips, and application processingcircuitry 426 may be on a separate chip or set of chips. In yet otheralternative embodiments, part or all of RF transceiver circuitry 422,baseband processing circuitry 424, and application processing circuitry426 may be combined in the same chip or set of chips. In someembodiments, RF transceiver circuitry 422 may be a part of interface414. RF transceiver circuitry 422 may condition RF signals forprocessing circuitry 420.

In certain embodiments, some or all of the functionality describedherein as being performed by a WD may be provided by processingcircuitry 420 executing instructions stored on device readable medium430, which in certain embodiments may be a computer-readable storagemedium. In alternative embodiments, some or all of the functionality maybe provided by processing circuitry 420 without executing instructionsstored on a separate or discrete device readable storage medium, such asin a hard-wired manner. In any of those particular embodiments, whetherexecuting instructions stored on a device readable storage medium ornot, processing circuitry 420 can be configured to perform the describedfunctionality. The benefits provided by such functionality are notlimited to processing circuitry 420 alone or to other components of WD410, but are enjoyed by WD 410 as a whole, and/or by end users and thewireless network generally.

Processing circuitry 420 may be configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being performed by a WD. These operations, asperformed by processing circuitry 420, may include processinginformation obtained by processing circuitry 420 by, for example,converting the obtained information into other information, comparingthe obtained information or converted information to information storedby WD 410, and/or performing one or more operations based on theobtained information or converted information, and as a result of saidprocessing making a determination.

Device readable medium 430 may be operable to store a computer program,software, an application including one or more of logic, rules, code,tables, etc. and/or other instructions capable of being executed byprocessing circuitry 420. Device readable medium 430 may includecomputer memory (e.g., Random Access Memory (RAM) or Read Only Memory(ROM)), mass storage media (e.g., a hard disk), removable storage media(e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or anyother volatile or non-volatile, non-transitory device readable and/orcomputer executable memory devices that store information, data, and/orinstructions that may be used by processing circuitry 420. In someembodiments, processing circuitry 420 and device readable medium 430 maybe considered to be integrated.

User interface equipment 432 may provide components that allow for ahuman user to interact with WD 410. Such interaction may be of manyforms, such as visual, audial, tactile, etc. User interface equipment432 may be operable to produce output to the user and to allow the userto provide input to WD 410. The type of interaction may vary dependingon the type of user interface equipment 432 installed in WD 410. Forexample, if WD 410 is a smart phone, the interaction may be via a touchscreen; if WD 410 is a smart meter, the interaction may be through ascreen that provides usage (e.g., the number of gallons used) or aspeaker that provides an audible alert (e.g., if smoke is detected).User interface equipment 432 may include input interfaces, devices andcircuits, and output interfaces, devices and circuits. User interfaceequipment 432 is configured to allow input of information into WD 410,and is connected to processing circuitry 420 to allow processingcircuitry 420 to process the input information. User interface equipment432 may include, for example, a microphone, a proximity or other sensor,keys/buttons, a touch display, one or more cameras, a USB port, or otherinput circuitry. User interface equipment 432 is also configured toallow output of information from WD 410, and to allow processingcircuitry 420 to output information from WD 410. User interfaceequipment 432 may include, for example, a speaker, a display, vibratingcircuitry, a USB port, a headphone interface, or other output circuitry.Using one or more input and output interfaces, devices, and circuits, ofuser interface equipment 432, WD 410 may communicate with end usersand/or the wireless network, and allow them to benefit from thefunctionality described herein.

Auxiliary equipment 434 is operable to provide more specificfunctionality which may not be generally performed by WDs. This maycomprise specialized sensors for doing measurements for variouspurposes, interfaces for additional types of communication such as wiredcommunications etc. The inclusion and type of components of auxiliaryequipment 434 may vary depending on the embodiment and/or scenario.

Power source 436 may, in some embodiments, be in the form of a batteryor battery pack. Other types of power sources, such as an external powersource (e.g., an electricity outlet), photovoltaic devices or powercells, may also be used. WD 410 may further comprise power circuitry 437for delivering power from power source 436 to the various parts of WD410 which need power from power source 436 to carry out anyfunctionality described or indicated herein. Power circuitry 437 may incertain embodiments comprise power management circuitry. Power circuitry437 may additionally or alternatively be operable to receive power froman external power source; in which case WD 410 may be connectable to theexternal power source (such as an electricity outlet) via inputcircuitry or an interface such as an electrical power cable. Powercircuitry 437 may also in certain embodiments be operable to deliverpower from an external power source to power source 436. This may be,for example, for the charging of power source 436. Power circuitry 437may perform any formatting, converting, or other modification to thepower from power source 436 to make the power suitable for therespective components of WD 410 to which power is supplied.

FIG. 11 illustrates an example embodiment of a UE, according to certainembodiments. As used herein, a user equipment or UE may not necessarilyhave a user in the sense of a human user who owns and/or operates therelevant device. Instead, a UE may represent a device that is intendedfor sale to, or operation by, a human user but which may not, or whichmay not initially, be associated with a specific human user (e.g., asmart sprinkler controller). Alternatively, a UE may represent a devicethat is not intended for sale to, or operation by, an end user but whichmay be associated with or operated for the benefit of a user (e.g., asmart power meter). UE 5200 may be any UE identified by the 3^(rd)Generation Partnership Project (3GPP), including a NB-IoT UE, a machinetype communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. UE 500,as illustrated in FIG. 11, is one example of a WD configured forcommunication in accordance with one or more communication standardspromulgated by the 3^(rd) Generation Partnership Project (3GPP), such as3GPP's GSM, UMTS, LTE, and/or 5G standards. As mentioned previously, theterm WD and UE may be used interchangeable. Accordingly, although FIG.11 is a UE, the components discussed herein are equally applicable to aWD, and vice-versa.

In FIG. 11, UE 500 includes processing circuitry 501 that is operativelycoupled to input/output interface 505, radio frequency (RF) interface509, network connection interface 511, memory 515 including randomaccess memory (RAM) 517, read-only memory (ROM) 519, and storage medium521 or the like, communication subsystem 531, power source 533, and/orany other component, or any combination thereof. Storage medium 521includes operating system 523, application program 525, and data 527. Inother embodiments, storage medium 521 may include other similar types ofinformation. Certain UEs may utilize all of the components shown in FIG.11, or only a subset of the components. The level of integration betweenthe components may vary from one UE to another UE. Further, certain UEsmay contain multiple instances of a component, such as multipleprocessors, memories, transceivers, transmitters, receivers, etc.

In FIG. 11, processing circuitry 501 may be configured to processcomputer instructions and data. Processing circuitry 501 may beconfigured to implement any sequential state machine operative toexecute machine instructions stored as machine-readable computerprograms in the memory, such as one or more hardware-implemented statemachines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logictogether with appropriate firmware; one or more stored program,general-purpose processors, such as a microprocessor or Digital SignalProcessor (DSP), together with appropriate software; or any combinationof the above. For example, the processing circuitry 501 may include twocentral processing units (CPUs). Data may be information in a formsuitable for use by a computer.

In the depicted embodiment, input/output interface 505 may be configuredto provide a communication interface to an input device, output device,or input and output device. UE 500 may be configured to use an outputdevice via input/output interface 505. An output device may use the sametype of interface port as an input device. For example, a USB port maybe used to provide input to and output from UE 500. The output devicemay be a speaker, a sound card, a video card, a display, a monitor, aprinter, an actuator, an emitter, a smartcard, another output device, orany combination thereof. UE 500 may be configured to use an input devicevia input/output interface 505 to allow a user to capture informationinto UE 500. The input device may include a touch-sensitive orpresence-sensitive display, a camera (e.g., a digital camera, a digitalvideo camera, a web camera, etc.), a microphone, a sensor, a mouse, atrackball, a directional pad, a trackpad, a scroll wheel, a smartcard,and the like. The presence-sensitive display may include a capacitive orresistive touch sensor to sense input from a user. A sensor may be, forinstance, an accelerometer, a gyroscope, a tilt sensor, a force sensor,a magnetometer, an optical sensor, a proximity sensor, another likesensor, or any combination thereof. For example, the input device may bean accelerometer, a magnetometer, a digital camera, a microphone, and anoptical sensor.

In FIG. 11, RF interface 509 may be configured to provide acommunication interface to RF components such as a transmitter, areceiver, and an antenna. Network connection interface 511 may beconfigured to provide a communication interface to network 543 a.Network 543 a may encompass wired and/or wireless networks such as alocal-area network (LAN), a wide-area network (WAN), a computer network,a wireless network, a telecommunications network, another like networkor any combination thereof. For example, network 543 a may comprise aWi-Fi network. Network connection interface 511 may be configured toinclude a receiver and a transmitter interface used to communicate withone or more other devices over a communication network according to oneor more communication protocols, such as Ethernet, TCP/IP, SONET, ATM,or the like. Network connection interface 511 may implement receiver andtransmitter functionality appropriate to the communication network links(e.g., optical, electrical, and the like). The transmitter and receiverfunctions may share circuit components, software or firmware, oralternatively may be implemented separately.

RAM 517 may be configured to interface via bus 502 to processingcircuitry 501 to provide storage or caching of data or computerinstructions during the execution of software programs such as theoperating system, application programs, and device drivers. ROM 519 maybe configured to provide computer instructions or data to processingcircuitry 501. For example, ROM 519 may be configured to store invariantlow-level system code or data for basic system functions such as basicinput and output (I/O), startup, or reception of keystrokes from akeyboard that are stored in a non-volatile memory. Storage medium 521may be configured to include memory such as RAM, ROM, programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), magneticdisks, optical disks, floppy disks, hard disks, removable cartridges, orflash drives. In one example, storage medium 521 may be configured toinclude operating system 523, application program 525 such as a webbrowser application, a widget or gadget engine or another application,and data file 527. Storage medium 521 may store, for use by UE 500, anyof a variety of various operating systems or combinations of operatingsystems.

Storage medium 521 may be configured to include a number of physicaldrive units, such as redundant array of independent disks (RAID), floppydisk drive, flash memory, USB flash drive, external hard disk drive,thumb drive, pen drive, key drive, high-density digital versatile disc(HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray opticaldisc drive, holographic digital data storage (HDDS) optical disc drive,external mini-dual in-line memory module (DIMM), synchronous dynamicrandom access memory (SDRAM), external micro-DIMM SDRAM, smartcardmemory such as a subscriber identity module or a removable user identity(SIM/RUIM) module, other memory, or any combination thereof. Storagemedium 521 may allow UE 500 to access computer-executable instructions,application programs or the like, stored on transitory or non-transitorymemory media, to off-load data, or to upload data. An article ofmanufacture, such as one utilizing a communication system may betangibly embodied in storage medium 521, which may comprise a devicereadable medium.

In FIG. 11, processing circuitry 501 may be configured to communicatewith network 543 b using communication subsystem 531. Network 543 a andnetwork 543 b may be the same network or networks or different networkor networks. Communication subsystem 531 may be configured to includeone or more transceivers used to communicate with network 543 b. Forexample, communication subsystem 531 may be configured to include one ormore transceivers used to communicate with one or more remotetransceivers of another device capable of wireless communication such asanother WD, UE, or base station of a radio access network (RAN)according to one or more communication protocols, such as IEEE 802.5,CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. Each transceiver mayinclude transmitter 533 and/or receiver 535 to implement transmitter orreceiver functionality, respectively, appropriate to the RAN links(e.g., frequency allocations and the like). Further, transmitter 533 andreceiver 535 of each transceiver may share circuit components, softwareor firmware, or alternatively may be implemented separately.

In the illustrated embodiment, the communication functions ofcommunication subsystem 531 may include data communication, voicecommunication, multimedia communication, short-range communications suchas Bluetooth, near-field communication, location-based communicationsuch as the use of the global positioning system (GPS) to determine alocation, another like communication function, or any combinationthereof. For example, communication subsystem 531 may include cellularcommunication, Wi-Fi communication, Bluetooth communication, and GPScommunication. Network 543 b may encompass wired and/or wirelessnetworks such as a local-area network (LAN), a wide-area network (WAN),a computer network, a wireless network, a telecommunications network,another like network or any combination thereof. For example, network543 b may be a cellular network, a Wi-Fi network, and/or a near-fieldnetwork. Power source 513 may be configured to provide alternatingcurrent (AC) or direct current (DC) power to components of UE 500.

The features, benefits and/or functions described herein may beimplemented in one of the components of UE 500 or partitioned acrossmultiple components of UE 500. Further, the features, benefits, and/orfunctions described herein may be implemented in any combination ofhardware, software or firmware. In one example, communication subsystem531 may be configured to include any of the components described herein.Further, processing circuitry 501 may be configured to communicate withany of such components over bus 502. In another example, any of suchcomponents may be represented by program instructions stored in memorythat when executed by processing circuitry 501 perform the correspondingfunctions described herein. In another example, the functionality of anyof such components may be partitioned between processing circuitry 501and communication subsystem 531. In another example, thenon-computationally intensive functions of any of such components may beimplemented in software or firmware and the computationally intensivefunctions may be implemented in hardware.

FIG. 12 is a schematic block diagram illustrating a virtualizationenvironment 800 in which functions implemented by some embodiments maybe virtualized. In the present context, virtualizing means creatingvirtual versions of apparatuses or devices which may includevirtualizing hardware platforms, storage devices and networkingresources. As used herein, virtualization can be applied to a node(e.g., a virtualized base station or a virtualized radio access node) orto a device (e.g., a UE, a wireless device or any other type ofcommunication device) or components thereof and relates to animplementation in which at least a portion of the functionality isimplemented as one or more virtual components (e.g., via one or moreapplications, components, functions, virtual machines or containersexecuting on one or more physical processing nodes in one or morenetworks).

In some embodiments, some or all of the functions described herein maybe implemented as virtual components executed by one or more virtualmachines implemented in one or more virtual environments 800 hosted byone or more of hardware nodes 830. Further, in embodiments in which thevirtual node is not a radio access node or does not require radioconnectivity (e.g., a core network node), then the network node may beentirely virtualized.

The functions may be implemented by one or more applications 820 (whichmay alternatively be called software instances, virtual appliances,network functions, virtual nodes, virtual network functions, etc.)operative to implement some of the features, functions, and/or benefitsof some of the embodiments disclosed herein. Applications 820 are run invirtualization environment 800 which provides hardware 830 comprisingprocessing circuitry 860 and memory 890. Memory 890 containsinstructions 895 executable by processing circuitry 860 wherebyapplication 820 is operative to provide one or more of the features,benefits, and/or functions disclosed herein.

Virtualization environment 800, comprises general-purpose orspecial-purpose network hardware devices 830 comprising a set of one ormore processors or processing circuitry 860, which may be commercialoff-the-shelf (COTS) processors, dedicated Application SpecificIntegrated Circuits (ASICs), or any other type of processing circuitryincluding digital or analog hardware components or special purposeprocessors. Each hardware device may comprise memory 890-1 which may benon-persistent memory for temporarily storing instructions 895 orsoftware executed by processing circuitry 860. Each hardware device maycomprise one or more network interface controllers (NICs) 870, alsoknown as network interface cards, which include physical networkinterface 880. Each hardware device may also include non-transitory,persistent, machine-readable storage media 890-2 having stored thereinsoftware 895 and/or instructions executable by processing circuitry 860.Software 895 may include any type of software including software forinstantiating one or more virtualization layers 850 (also referred to ashypervisors), software to execute virtual machines 840 as well assoftware allowing it to execute functions, features and/or benefitsdescribed in relation with some embodiments described herein.

Virtual machines 840, comprise virtual processing, virtual memory,virtual networking or interface and virtual storage, and may be run by acorresponding virtualization layer 850 or hypervisor. Differentembodiments of the instance of virtual appliance 820 may be implementedon one or more of virtual machines 840, and the implementations may bemade in different ways.

During operation, processing circuitry 860 executes software 895 toinstantiate the hypervisor or virtualization layer 850, which maysometimes be referred to as a virtual machine monitor (VMM).Virtualization layer 850 may present a virtual operating platform thatappears like networking hardware to virtual machine 840.

As shown in FIG. 12, hardware 830 may be a standalone network node withgeneric or specific components. Hardware 830 may comprise antenna 8225and may implement some functions via virtualization. Alternatively,hardware 830 may be part of a larger cluster of hardware (e.g. such asin a data center or customer premise equipment (CPE)) where manyhardware nodes work together and are managed via management andorchestration (MANO) 8100, which, among others, oversees lifecyclemanagement of applications 820.

Virtualization of the hardware is in some contexts referred to asnetwork function virtualization (NFV). NFV may be used to consolidatemany network equipment types onto industry standard high volume serverhardware, physical switches, and physical storage, which can be locatedin data centers, and customer premise equipment.

In the context of NFV, virtual machine 840 may be a softwareimplementation of a physical machine that runs programs as if they wereexecuting on a physical, non-virtualized machine. Each of virtualmachines 840, and that part of hardware 830 that executes that virtualmachine, be it hardware dedicated to that virtual machine and/orhardware shared by that virtual machine with others of the virtualmachines 840, forms a separate virtual network elements (VNE).

Still in the context of NFV, Virtual Network Function (VNF) isresponsible for handling specific network functions that run in one ormore virtual machines 840 on top of hardware networking infrastructure830 and corresponds to application 820 in FIG. 12.

In some embodiments, one or more radio units 8200 that each include oneor more transmitters 8220 and one or more receivers 8210 may be coupledto one or more antennas 8225. Radio units 8200 may communicate directlywith hardware nodes 830 via one or more appropriate network interfacesand may be used in combination with the virtual components to provide avirtual node with radio capabilities, such as a radio access node or abase station.

In some embodiments, some signalling can be effected with the use ofcontrol system 8230 which may alternatively be used for communicationbetween the hardware nodes 830 and radio units 8200.

FIG. 13 illustrates a telecommunication network connected via anintermediate network to a host computer in accordance with someembodiments. With reference to FIG. 13, in accordance with anembodiment, a communication system includes telecommunication network910, such as a 3GPP-type cellular network, which comprises accessnetwork 911, such as a radio access network, and core network 914.Access network 911 comprises a plurality of base stations 912 a, 912 b,912 c, such as NBs, eNBs, gNBs or other types of wireless access points,each defining a corresponding coverage area 913 a, 913 b, 913 c. Eachbase station 912 a, 912 b, 912 c is connectable to core network 914 overa wired or wireless connection 915. A first UE 991 located in coveragearea 913 c is configured to wirelessly connect to, or be paged by, thecorresponding base station 912 c. A second UE 992 in coverage area 913 ais wirelessly connectable to the corresponding base station 912 a. Whilea plurality of UEs 991, 992 are illustrated in this example, thedisclosed embodiments are equally applicable to a situation where a soleUE is in the coverage area or where a sole UE is connecting to thecorresponding base station 912.

Telecommunication network 910 is itself connected to host computer 930,which may be embodied in the hardware and/or software of a standaloneserver, a cloud-implemented server, a distributed server or asprocessing resources in a server farm. Host computer 930 may be underthe ownership or control of a service provider, or may be operated bythe service provider or on behalf of the service provider. Connections921 and 922 between telecommunication network 910 and host computer 930may extend directly from core network 914 to host computer 930 or may govia an optional intermediate network 920. Intermediate network 920 maybe one of, or a combination of more than one of, a public, private orhosted network; intermediate network 920, if any, may be a backbonenetwork or the Internet; in particular, intermediate network 920 maycomprise two or more sub-networks (not shown).

The communication system of FIG. 13 as a whole enables connectivitybetween the connected UEs 991, 992 and host computer 930. Theconnectivity may be described as an over-the-top (OTT) connection 950.Host computer 930 and the connected UEs 991, 992 are configured tocommunicate data and/or signaling via OTT connection 950, using accessnetwork 911, core network 914, any intermediate network 920 and possiblefurther infrastructure (not shown) as intermediaries. OTT connection 950may be transparent in the sense that the participating communicationdevices through which OTT connection 950 passes are unaware of routingof uplink and downlink communications. For example, base station 912 maynot or need not be informed about the past routing of an incomingdownlink communication with data originating from host computer 930 tobe forwarded (e.g., handed over) to a connected UE 991. Similarly, basestation 912 need not be aware of the future routing of an outgoinguplink communication originating from the UE 991 towards the hostcomputer 930.

FIG. 14 illustrates a host computer communicating via a base stationwith a user equipment over a partially wireless connection in accordancewith some embodiments. Example implementations, in accordance with anembodiment, of the UE, base station and host computer discussed in thepreceding paragraphs will now be described with reference to FIG. 14. Incommunication system 1000, host computer 1010 comprises hardware 1015including communication interface 1016 configured to set up and maintaina wired or wireless connection with an interface of a differentcommunication device of communication system 1000. Host computer 1010further comprises processing circuitry 1018, which may have storageand/or processing capabilities. In particular, processing circuitry 1018may comprise one or more programmable processors, application-specificintegrated circuits, field programmable gate arrays or combinations ofthese (not shown) adapted to execute instructions. Host computer 1010further comprises software 1011, which is stored in or accessible byhost computer 1010 and executable by processing circuitry 1018. Software1011 includes host application 1012. Host application 1012 may beoperable to provide a service to a remote user, such as UE 1030connecting via OTT connection 1050 terminating at UE 1030 and hostcomputer 1010. In providing the service to the remote user, hostapplication 1012 may provide user data which is transmitted using OTTconnection 1050.

Communication system 1000 further includes base station 1020 provided ina telecommunication system and comprising hardware 1025 enabling it tocommunicate with host computer 1010 and with UE 1030. Hardware 1025 mayinclude communication interface 1026 for setting up and maintaining awired or wireless connection with an interface of a differentcommunication device of communication system 1000, as well as radiointerface 1027 for setting up and maintaining at least wirelessconnection 1070 with UE 1030 located in a coverage area (not shown inFIG. 14) served by base station 1020. Communication interface 1026 maybe configured to facilitate connection 1060 to host computer 1010.Connection 1060 may be direct or it may pass through a core network (notshown in FIG. 14) of the telecommunication system and/or through one ormore intermediate networks outside the telecommunication system. In theembodiment shown, hardware 1025 of base station 1020 further includesprocessing circuitry 1028, which may comprise one or more programmableprocessors, application-specific integrated circuits, field programmablegate arrays or combinations of these (not shown) adapted to executeinstructions. Base station 1020 further has software 1021 storedinternally or accessible via an external connection.

Communication system 1000 further includes UE 1030 already referred to.Its hardware 1035 may include radio interface 1037 configured to set upand maintain wireless connection 1070 with a base station serving acoverage area in which UE 1030 is currently located. Hardware 1035 of UE1030 further includes processing circuitry 1038, which may comprise oneor more programmable processors, application-specific integratedcircuits, field programmable gate arrays or combinations of these (notshown) adapted to execute instructions. UE 1030 further comprisessoftware 1031, which is stored in or accessible by UE 1030 andexecutable by processing circuitry 1038. Software 1031 includes clientapplication 1032. Client application 1032 may be operable to provide aservice to a human or non-human user via UE 1030, with the support ofhost computer 1010. In host computer 1010, an executing host application1012 may communicate with the executing client application 1032 via OTTconnection 1050 terminating at UE 1030 and host computer 1010. Inproviding the service to the user, client application 1032 may receiverequest data from host application 1012 and provide user data inresponse to the request data. OTT connection 1050 may transfer both therequest data and the user data. Client application 1032 may interactwith the user to generate the user data that it provides.

It is noted that host computer 1010, base station 1020 and UE 1030illustrated in FIG. 14 may be similar or identical to host computer 930,one of base stations 912 a, 912 b, 912 c and one of UEs 991, 992 of FIG.13, respectively. This is to say, the inner workings of these entitiesmay be as shown in FIG. 14 and independently, the surrounding networktopology may be that of FIG. 13.

In FIG. 14, OTT connection 1050 has been drawn abstractly to illustratethe communication between host computer 1010 and UE 1030 via basestation 1020, without explicit reference to any intermediary devices andthe precise routing of messages via these devices. Networkinfrastructure may determine the routing, which it may be configured tohide from UE 1030 or from the service provider operating host computer1010, or both. While OTT connection 1050 is active, the networkinfrastructure may further take decisions by which it dynamicallychanges the routing (e.g., on the basis of load balancing considerationor reconfiguration of the network).

Wireless connection 1070 between UE 1030 and base station 1020 is inaccordance with the teachings of the embodiments described throughoutthis disclosure. One or more of the various embodiments improve theperformance of OTT services provided to UE 1030 using OTT connection1050, in which wireless connection 1070 forms the last segment. Moreprecisely, the teachings of these embodiments may improve the handoverprocedure and thereby provide benefits such as fewer disruptions ofservice.

A measurement procedure may be provided for the purpose of monitoringdata rate, latency and other factors on which the one or moreembodiments improve. There may further be an optional networkfunctionality for reconfiguring OTT connection 1050 between hostcomputer 1010 and UE 1030, in response to variations in the measurementresults. The measurement procedure and/or the network functionality forreconfiguring OTT connection 1050 may be implemented in software 1011and hardware 1015 of host computer 1010 or in software 1031 and hardware1035 of UE 1030, or both. In embodiments, sensors (not shown) may bedeployed in or in association with communication devices through whichOTT connection 1050 passes; the sensors may participate in themeasurement procedure by supplying values of the monitored quantitiesexemplified above, or supplying values of other physical quantities fromwhich software 1011, 1031 may compute or estimate the monitoredquantities. The reconfiguring of OTT connection 1050 may include messageformat, retransmission settings, preferred routing etc.; thereconfiguring need not affect base station 1020, and it may be unknownor imperceptible to base station 1020. Such procedures andfunctionalities may be known and practiced in the art. In certainembodiments, measurements may involve proprietary UE signalingfacilitating host computer 1010's measurements of throughput,propagation times, latency and the like. The measurements may beimplemented in that software 1011 and 1031 causes messages to betransmitted, in particular empty or ‘dummy’ messages, using OTTconnection 1050 while it monitors propagation times, errors etc.

FIG. 15 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 13 and 14. Forsimplicity of the present disclosure, only drawing references to FIG. 15will be included in this section. In step 1110, the host computerprovides user data. In substep 1111 (which may be optional) of step1110, the host computer provides the user data by executing a hostapplication. In step 1120, the host computer initiates a transmissioncarrying the user data to the UE. In step 1130 (which may be optional),the base station transmits to the UE the user data which was carried inthe transmission that the host computer initiated, in accordance withthe teachings of the embodiments described throughout this disclosure.In step 1140 (which may also be optional), the UE executes a clientapplication associated with the host application executed by the hostcomputer.

FIG. 16 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 13 and 14. Forsimplicity of the present disclosure, only drawing references to FIG. 16will be included in this section. In step 1210 of the method, the hostcomputer provides user data. In an optional substep (not shown) the hostcomputer provides the user data by executing a host application. In step1220, the host computer initiates a transmission carrying the user datato the UE. The transmission may pass via the base station, in accordancewith the teachings of the embodiments described throughout thisdisclosure. In step 1230 (which may be optional), the UE receives theuser data carried in the transmission.

FIG. 17 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 13 and 14. Forsimplicity of the present disclosure, only drawing references to FIG. 17will be included in this section. In step 1310 (which may be optional),the UE receives input data provided by the host computer. Additionallyor alternatively, in step 1320, the UE provides user data. In substep1321 (which may be optional) of step 1320, the UE provides the user databy executing a client application. In substep 1311 (which may beoptional) of step 1310, the UE executes a client application whichprovides the user data in reaction to the received input data providedby the host computer. In providing the user data, the executed clientapplication may further consider user input received from the user.Regardless of the specific manner in which the user data was provided,the UE initiates, in substep 1330 (which may be optional), transmissionof the user data to the host computer. In step 1340 of the method, thehost computer receives the user data transmitted from the UE, inaccordance with the teachings of the embodiments described throughoutthis disclosure.

FIG. 18 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 13 and 14. Forsimplicity of the present disclosure, only drawing references to FIG. 18will be included in this section. In step 1410 (which may be optional),in accordance with the teachings of the embodiments described throughoutthis disclosure, the base station receives user data from the UE. Instep 1420 (which may be optional), the base station initiatestransmission of the received user data to the host computer. In step1430 (which may be optional), the host computer receives the user datacarried in the transmission initiated by the base station.

Any appropriate steps, methods, features, functions, or benefitsdisclosed herein may be performed through one or more functional unitsor modules of one or more virtual apparatuses. Each virtual apparatusmay comprise a number of these functional units. These functional unitsmay be implemented via processing circuitry, which may include one ormore microprocessor or microcontrollers, as well as other digitalhardware, which may include digital signal processors (DSPs),special-purpose digital logic, and the like. The processing circuitrymay be configured to execute program code stored in memory, which mayinclude one or several types of memory such as read-only memory (ROM),random-access memory (RAM), cache memory, flash memory devices, opticalstorage devices, etc. Program code stored in memory includes programinstructions for executing one or more telecommunications and/or datacommunications protocols as well as instructions for carrying out one ormore of the techniques described herein. In some implementations, theprocessing circuitry may be used to cause the respective functional unitto perform corresponding functions according one or more embodiments ofthe present disclosure.

The term unit may have conventional meaning in the field of electronics,electrical devices and/or electronic devices and may include, forexample, electrical and/or electronic circuitry, devices, modules,processors, memories, logic solid state and/or discrete devices,computer programs or instructions for carrying out respective tasks,procedures, computations, outputs, and/or displaying functions, and soon, as such as those that are described herein.

FIG. 19 illustrates a method 1500 by a wireless device 410 forbeam-based random access, according to certain embodiments. The methodbegins at step 1510 when wireless device 410 receives, from a networknode 415, a handover command. The handover command comprises at leastone suitability threshold.

In a particular embodiment, the handover command is received from anetwork node that is connected to the wireless device. For example, thehandover command may be generated by a target network node performing ahandover of the wireless device from the source network node to thetarget network node, in a particular embodiment.

At step 1520, wireless device 410 performs measurements of each of aplurality of beams detected by the wireless device 410.

At step 1530, wireless device 410 compares the measurements of theplurality of beams to the at least one suitability threshold.

At step 1540, wireless device 410 selects a particular beam of theplurality of beams based on the comparison of the measurements of theplurality of beams to the at least one suitability threshold.

At step 1550, wireless device 410 initiates a random access procedure.In a particular embodiment, initiating the random access procedure mayinclude using the particular beam selected from the plurality of beamsto transmit random access preamble.

In a particular embodiment, the at least one suitability thresholdcomprises at least one PRACH suitability threshold or at least one RACHsuitability threshold.

In a particular embodiment, the at least one suitability threshold mayinclude at least one minimum radio quality. Each measurement of theplurality of beams may be compared to the at least one minimum radioquality, and the particular beam that has an associated measurement thatis greater than the at least one minimum radio quality may be selected.

In another particular embodiment, the at least one suitability thresholdcomprises at least one minimum reference signal received power (RSRP).

In yet another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, and each ofthe plurality of suitability thresholds is associated with a differentone of a plurality of reference signals.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with CBRA, and asecond of the plurality of suitability thresholds is associated withcontention free random access (CFRA). The second of the plurality ofsuitability thresholds may be lower than the first of the plurality ofsuitability thresholds.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is for synchronization signalblock (SSB) based handover, and a second of the plurality of suitabilitythresholds is for channel state information-reference signal (CSI-RS)based handover.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with an initialpreamble transmission, and a second of the plurality of suitabilitythresholds is associated with a preamble retransmission. The second ofthe plurality of suitability thresholds is lower than the first of theplurality of suitability thresholds.

In certain embodiments, the method for beam-based random access asdescribed above may be performed by a computer networking virtualapparatus. FIG. 20 illustrates an example virtual computing device 1600for beam-based random access, according to certain embodiments. Incertain embodiments, virtual computing device 1600 may include modulesfor performing steps similar to those described above with regard to themethod illustrated and described in FIG. 19. For example, virtualcomputing device 1600 may include a receiving module 1610, a performingmodule 1620, a comparing module 1630, a selecting module 1640, aninitiating module 1650, and any other suitable modules for beam-basedrandom access. In some embodiments, one or more of the modules may beimplemented using processing circuitry 420 of FIG. 10. In certainembodiments, the functions of two or more of the various modules may becombined into a single module.

The receiving module 1610 may perform the receiving functions of virtualcomputing device 1600. For example, in a particular embodiment,receiving module 1610 may receive, from a network node 415, a handovercommand. The handover command comprises at least one suitabilitythreshold.

The performing module 1620 may perform the performing functions ofvirtual computing device 1600. For example, in a particular embodiment,performing module 1620 may perform measurements of each of a pluralityof beams detected by the wireless device 410.

The comparing module 1630 may perform the comparing functions of virtualcomputing device 1600. For example, in a particular embodiment,comparing module 1630 may compare the measurements of the plurality ofbeams to the at least one suitability threshold.

The selecting module 1640 may perform the selecting functions of virtualcomputing device 1600. For example, in a particular embodiment,selecting module 1640 may select a particular beam of the plurality ofbeams based on the comparison of the measurements of the plurality ofbeams to the at least one suitability threshold.

The initiating module 1650 may perform the initiating functions ofvirtual computing device 1600. For example, in a particular embodiment,imitating module 1650 may initiate a random access procedure.

Other embodiments of virtual computing device 1600 may includeadditional components beyond those shown in FIG. 20 that may beresponsible for providing certain aspects of the wireless devices'sfunctionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the solutions described above). The various different types ofwireless devices 410 may include components having the same physicalhardware but configured (e.g., via programming) to support differentradio access technologies, or may represent partly or entirely differentphysical components.

FIG. 21 illustrates a method 1700 by a target network node 415 forimitating beam-based random access with a wireless device, according tocertain embodiments. The method 1700 begins at step 1710 when the targetnetwork node 415 transmits, to a source network node 415 connected tothe wireless device 410, a handover command. The handover commandcomprises at least one suitability threshold that includes a minimumradio quality for use by the wireless device in selecting a particularone of a plurality of beams to initiate handover to the target networknode.

At step 1720, the target network node 415 receives, from the wirelessdevice 410, a random access preamble.

In a particular embodiment, prior to transmitting the handover commandcomprising the at least one suitability threshold to the source networknode 415, the method further includes the target network node 415receiving a measurement reporting parameter associated with the wirelessdevice 410 from the source network node and determining the at least onesuitability threshold based on the measurement reporting parameterassociated with the wireless device.

In a particular embodiment, the method may further include transmittinga message to the source network node 415 that includes the at least onesuitability threshold for use by the source network node 415 indetermining a measurement reporting parameter for the wireless device410.

In a particular embodiment, the at least one suitability thresholdcomprises at least one PRACH suitability threshold or at least one RACHsuitability threshold.

In a particular embodiment, the at least one suitability threshold mayinclude at least one minimum radio quality. Each measurement of theplurality of beams may be compared to the at least one minimum radioquality, and the particular beam that has an associated measurement thatis greater than the at least one minimum radio quality may be selected.

In another particular embodiment, the at least one suitability thresholdcomprises at least one minimum reference signal received power (RSRP).

In yet another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, and each ofthe plurality of suitability thresholds is associated with a differentone of a plurality of reference signals.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with CBRA, and asecond of the plurality of suitability thresholds is associated withcontention free random access (CFRA). The second of the plurality ofsuitability thresholds may be lower than the first of the plurality ofsuitability thresholds.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is for synchronization signalblock (SSB) based handover, and a second of the plurality of suitabilitythresholds is for channel state information-reference signal (CSI-RS)based handover.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with an initialpreamble transmission, and a second of the plurality of suitabilitythresholds is associated with a preamble retransmission. The second ofthe plurality of suitability thresholds is lower than the first of theplurality of suitability thresholds.

In certain embodiments, the method for beam-based random access asdescribed above may be performed by a computer networking virtualapparatus. FIG. 22 illustrates an example virtual computing device 1800for beam-based random access, according to certain embodiments. Incertain embodiments, virtual computing device 1800 may include modulesfor performing steps similar to those described above with regard to themethod illustrated and described in FIG. 21. For example, virtualcomputing device 1800 may include a transmitting module 1810, areceiving module 1820, and any other suitable modules for beam-basedrandom access. In some embodiments, one or more of the modules may beimplemented using processing circuitry 470 of FIG. 9. In certainembodiments, the functions of two or more of the various modules may becombined into a single module.

The transmitting module 1810 may perform the transmitting functions ofvirtual computing device 1800. For example, in a particular embodiment,transmitting module 1810 may transmit, to a source network node 415connected to the wireless device 410, a handover command. The handovercommand comprises at least one suitability threshold that includes aminimum radio quality for use by the wireless device in selecting aparticular one of a plurality of beams to initiate handover to thetarget network node.

The receiving module 1820 may perform the receiving functions of virtualcomputing device 1800. For example, in a particular embodiment,receiving module 1820 may receive, from the wireless device 410, arandom access preamble.

Other embodiments of virtual computing device 1800 may includeadditional components beyond those shown in FIG. 22 that may beresponsible for providing certain aspects of the network node'sfunctionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the solutions described above). The various different types ofnetwork nodes 415 may include components having the same physicalhardware but configured (e.g., via programming) to support differentradio access technologies, or may represent partly or entirely differentphysical components.

FIG. 23 illustrates a method 1900 by a source network node 415 forbeam-based random access with a wireless device, according to certainembodiments. The method 1900 begins at step 1910 when the source networknode 415 receives, from a target network node 415, a handover commandcomprising at least one suitability threshold.

At step 1920, source network node 415 transmits, the handover commandcomprising the at least one suitability threshold to a wireless device410 connected to the source network node 415 to initiate handover of thewireless device 410 to the target network node 415. The at least onesuitability threshold includes a minimum radio quality for selecting aparticular one of a plurality of beams by the wireless device 410 toinitiate handover with the target network node 415.

In a particular embodiment, prior to receiving the handover commandcomprising the at least one suitability threshold from the targetnetwork node 415, source network node 415 may transmit a measurementreporting parameter associated with the wireless device 410 to thetarget network node 415 for use by the target network node 415 indetermining the at least one suitability threshold.

In a particular embodiment, the at least one suitability thresholdcomprises at least one PRACH suitability threshold or at least one RACHsuitability threshold.

In a particular embodiment, the at least one suitability threshold mayinclude at least one minimum radio quality. Each measurement of theplurality of beams may be compared to the at least one minimum radioquality, and the particular beam that has an associated measurement thatis greater than the at least one minimum radio quality may be selected.

In another particular embodiment, the at least one suitability thresholdcomprises at least one minimum reference signal received power (RSRP).

In yet another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, and each ofthe plurality of suitability thresholds is associated with a differentone of a plurality of reference signals.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with CBRA, and asecond of the plurality of suitability thresholds is associated withcontention free random access (CFRA). The second of the plurality ofsuitability thresholds may be lower than the first of the plurality ofsuitability thresholds.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is for synchronization signalblock (SSB) based handover, and a second of the plurality of suitabilitythresholds is for channel state information-reference signal (CSI-RS)based handover.

In still another particular embodiment, the at least one suitabilitythreshold comprises a plurality of suitability thresholds, a first ofthe plurality of suitability thresholds is associated with an initialpreamble transmission, and a second of the plurality of suitabilitythresholds is associated with a preamble retransmission. The second ofthe plurality of suitability thresholds is lower than the first of theplurality of suitability thresholds.

In certain embodiments, the method for beam-based random access asdescribed above may be performed by a computer networking virtualapparatus. FIG. 24 illustrates an example virtual computing device 2000for beam-based random access, according to certain embodiments. Incertain embodiments, virtual computing device 2000 may include modulesfor performing steps similar to those described above with regard to themethod illustrated and described in FIG. 23. For example, virtualcomputing device 2000 may include a receiving module 2010, atransmitting module 2020, and any other suitable modules for beam-basedrandom access. In some embodiments, one or more of the modules may beimplemented using processing circuitry 470 of FIG. 9. In certainembodiments, the functions of two or more of the various modules may becombined into a single module.

The receiving module 2010 may perform the receiving functions of virtualcomputing device 2000. For example, in a particular embodiment,receiving module 2010 may receive, from a target network node 415, ahandover command comprising at least one suitability threshold.

The transmitting module 2020 may perform the transmitting functions ofvirtual computing device 2000. For example, in a particular embodiment,transmitting module 2020 may transmit the handover command comprisingthe at least one suitability threshold to a wireless device 410connected to the source network node 415 to initiate handover of thewireless device 410 to the target network node 415. The at least onesuitability threshold includes a minimum radio quality for selecting aparticular one of a plurality of beams by the wireless device 410 toinitiate handover with the target network node 415.

Other embodiments of virtual computing device 2000 may includeadditional components beyond those shown in FIG. 24 that may beresponsible for providing certain aspects of the network node'sfunctionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the solutions described above). The various different types ofnetwork nodes 415 may include components having the same physicalhardware but configured (e.g., via programming) to support differentradio access technologies, or may represent partly or entirely differentphysical components.

ADDITIONAL EMBODIMENTS Group A Embodiments

-   -   1. A method performed by a wireless device for multi-beam random        access procedure in handover execution, the method comprising        one or more of the steps discussed above.    -   2. The method of any of the previous embodiments, further        comprising:        -   providing user data; and    -   forwarding the user data to a host computer via the transmission        to the base station.

Group B Embodiments

-   -   3. A method performed by a base station for multi-beam random        access procedure in handover execution, the method comprising        one or more of the steps discussed above.    -   4. The method of any of the previous embodiments, further        comprising:        -   obtaining user data; and        -   forwarding the user data to a host computer or a wireless            device.

Group C Embodiments

-   -   5. A wireless device for multi-beam random access procedure in        handover execution, the wireless device comprising:        -   processing circuitry configured to perform any of the steps            of any of the Group A embodiments; and        -   power supply circuitry configured to supply power to the            wireless device.    -   6. A base station for multi-beam random access procedure in        handover execution, the base station comprising:        -   processing circuitry configured to perform any of the steps            of any of the Group B embodiments;        -   power supply circuitry configured to supply power to the            wireless device.    -   7. A user equipment (UE) for multi-beam random access procedure        in handover execution, the UE comprising:        -   an antenna configured to send and receive wireless signals;        -   radio front-end circuitry connected to the antenna and to            processing circuitry, and configured to condition signals            communicated between the antenna and the processing            circuitry;        -   the processing circuitry being configured to perform any of            the steps of any of the Group A embodiments;        -   an input interface connected to the processing circuitry and            configured to allow input of information into the UE to be            processed by the processing circuitry;        -   an output interface connected to the processing circuitry            and configured to output information from the UE that has            been processed by the processing circuitry; and        -   a battery connected to the processing circuitry and            configured to supply power to the UE.    -   8. A communication system including a host computer comprising:        -   processing circuitry configured to provide user data; and        -   a communication interface configured to forward the user            data to a cellular network for transmission to a user            equipment (UE),        -   wherein the cellular network comprises a base station having            a radio interface and processing circuitry, the base            station's processing circuitry configured to perform any of            the steps of any of the Group B embodiments.    -   9. The communication system of the pervious embodiment further        including the base station.    -   10. The communication system of the previous 2 embodiments,        further including the UE, wherein the UE is configured to        communicate with the base station.    -   11. The communication system of the previous 3 embodiments,        wherein:        -   the processing circuitry of the host computer is configured            to execute a host application, thereby providing the user            data; and        -   the UE comprises processing circuitry configured to execute            a client application associated with the host application.    -   12. A method implemented in a communication system including a        host computer, a base station and a user equipment (UE), the        method comprising:        -   at the host computer, providing user data; and        -   at the host computer, initiating a transmission carrying the            user data to the UE via a cellular network comprising the            base station, wherein the base station performs any of the            steps of any of the Group B embodiments.    -   13. The method of the previous embodiment, further comprising,        at the base station, transmitting the user data.    -   14. The method of the previous 2 embodiments, wherein the user        data is provided at the host computer by executing a host        application, the method further comprising, at the UE, executing        a client application associated with the host application.    -   15. A user equipment (UE) configured to communicate with a base        station, the UE comprising a radio interface and processing        circuitry configured to performs the of the previous 3        embodiments.    -   16. A communication system including a host computer comprising:        -   processing circuitry configured to provide user data; and        -   a communication interface configured to forward user data to            a cellular network for transmission to a user equipment            (UE),        -   wherein the UE comprises a radio interface and processing            circuitry, the UE's components configured to perform any of            the steps of any of the Group A embodiments.    -   17. The communication system of the previous embodiment, wherein        the cellular network further includes a base station configured        to communicate with the UE.    -   18. The communication system of the previous 2 embodiments,        wherein:        -   the processing circuitry of the host computer is configured            to execute a host application, thereby providing the user            data; and        -   the UE's processing circuitry is configured to execute a            client application associated with the host application.    -   19. A method implemented in a communication system including a        host computer, a base station and a user equipment (UE), the        method comprising:        -   at the host computer, providing user data; and        -   at the host computer, initiating a transmission carrying the            user data to the UE via a cellular network comprising the            base station, wherein the UE performs any of the steps of            any of the Group A embodiments.    -   20. The method of the previous embodiment, further comprising at        the UE, receiving the user data from the base station.    -   21. A communication system including a host computer comprising:        -   communication interface configured to receive user data            originating from a transmission from a user equipment (UE)            to a base station,        -   wherein the UE comprises a radio interface and processing            circuitry, the UE's processing circuitry configured to            perform any of the steps of any of the Group A embodiments.    -   22. The communication system of the previous embodiment, further        including the UE.    -   23. The communication system of the previous 2 embodiments,        further including the base station, wherein the base station        comprises a radio interface configured to communicate with the        UE and a communication interface configured to forward to the        host computer the user data carried by a transmission from the        UE to the base station.    -   24. The communication system of the previous 3 embodiments,        wherein:        -   the processing circuitry of the host computer is configured            to execute a host application; and        -   the UE's processing circuitry is configured to execute a            client application associated with the host application,            thereby providing the user data.    -   25. The communication system of the previous 4 embodiments,        wherein:        -   the processing circuitry of the host computer is configured            to execute a host application, thereby providing request            data; and        -   the UE's processing circuitry is configured to execute a            client application associated with the host application,            thereby providing the user data in response to the request            data.    -   26. A method implemented in a communication system including a        host computer, a base station and a user equipment (UE), the        method comprising:        -   at the host computer, receiving user data transmitted to the            base station from the UE, wherein the UE performs any of the            steps of any of the Group A embodiments.    -   27. The method of the previous embodiment, further comprising,        at the UE, providing the user data to the base station.    -   28. The method of the previous 2 embodiments, further        comprising:        -   at the UE, executing a client application, thereby providing            the user data to be transmitted; and        -   at the host computer, executing a host application            associated with the client application.    -   29. The method of the previous 3 embodiments, further        comprising:        -   at the UE, executing a client application; and        -   at the UE, receiving input data to the client application,            the input data being provided at the host computer by            executing a host application associated with the client            application,        -   wherein the user data to be transmitted is provided by the            client application in response to the input data.    -   30. A communication system including a host computer comprising        a communication interface configured to receive user data        originating from a transmission from a user equipment (UE) to a        base station, wherein the base station comprises a radio        interface and processing circuitry, the base station's        processing circuitry configured to perform any of the steps of        any of the Group B embodiments.    -   31. The communication system of the previous embodiment further        including the base station.    -   32. The communication system of the previous 2 embodiments,        further including the UE, wherein the UE is configured to        communicate with the base station.    -   33. The communication system of the previous 3 embodiments,        wherein:        -   the processing circuitry of the host computer is configured            to execute a host application;        -   the UE is configured to execute a client application            associated with the host application, thereby providing the            user data to be received by the host computer.    -   34. A method implemented in a communication system including a        host computer, a base station and a user equipment (UE), the        method comprising:        -   at the host computer, receiving, from the base station, user            data originating from a transmission which the base station            has received from the UE, wherein the UE performs any of the            steps of any of the Group A embodiments.    -   35. The method of the previous embodiment, further comprising at        the base station, receiving the user data from the UE.    -   36. The method of the previous 2 embodiments, further comprising        at the base station, initiating a transmission of the received        user data to the host computer.

Abbreviations

At least some of the following abbreviations may be used in thisdisclosure. If there is an inconsistency between abbreviations,preference should be given to how it is used above. If listed multipletimes below, the first listing should be preferred over any subsequentlisting(s).

-   1×RTT CDMA2000 1× Radio Transmission Technology-   3GPP 3rd Generation Partnership Project-   5G 5th Generation-   ABS Almost Blank Subframe-   ARQ Automatic Repeat Request-   AWGN Additive White Gaussian Noise-   BCCH Broadcast Control Channel-   BCH Broadcast Channel-   CA Carrier Aggregation-   CC Carrier Component-   CCCH SDU Common Control Channel SDU-   CDMA Code Division Multiplexing Access-   CGI Cell Global Identifier-   CIR Channel Impulse Response-   CP Cyclic Prefix-   CPICH Common Pilot Channel-   CPICH Ec/No CPICH Received energy per chip divided by the power    density in the band-   CQI Channel Quality information-   C-RNTI Cell RNTI-   CSI Channel State Information-   DCCH Dedicated Control Channel-   DL Downlink-   DM Demodulation-   DMRS Demodulation Reference Signal-   DRX Discontinuous Reception-   DTX Discontinuous Transmission-   DTCH Dedicated Traffic Channel-   DUT Device Under Test-   E-CID Enhanced Cell-ID (positioning method)-   E-SMLC Evolved-Serving Mobile Location Centre-   ECGI Evolved CGI-   eNB E-UTRAN NodeB-   ePDCCH enhanced Physical Downlink Control Channel-   E-SMLC evolved Serving Mobile Location Center-   E-UTRA Evolved UTRA-   E-UTRAN Evolved UTRAN-   FDD Frequency Division Duplex-   FFS For Further Study-   GERAN GSM EDGE Radio Access Network-   gNB Base station in NR-   GNSS Global Navigation Satellite System-   GSM Global System for Mobile communication-   HARQ Hybrid Automatic Repeat Request-   HO Handover-   HSPA High Speed Packet Access-   HRPD High Rate Packet Data-   LOS Line of Sight-   LPP LTE Positioning Protocol-   LTE Long-Term Evolution-   MAC Medium Access Control-   MBMS Multimedia Broadcast Multicast Services-   MBSFN Multimedia Broadcast multicast service Single Frequency    Network-   MBSFN ABS MBSFN Almost Blank Subframe-   MDT Minimization of Drive Tests-   MIB Master Information Block-   MME Mobility Management Entity-   MSC Mobile Switching Center-   NPDCCH Narrowband Physical Downlink Control Channel-   NR New Radio-   OCNG OFDMA Channel Noise Generator-   OFDM Orthogonal Frequency Division Multiplexing-   OFDMA Orthogonal Frequency Division Multiple Access-   OSS Operations Support System-   OTDOA Observed Time Difference of Arrival-   O&M Operation and Maintenance-   PBCH Physical Broadcast Channel-   P-CCPCH Primary Common Control Physical Channel-   PCell Primary Cell-   PCFICH Physical Control Format Indicator Channel-   PDCCH Physical Downlink Control Channel-   PDP Profile Delay Profile-   PDSCH Physical Downlink Shared Channel-   PGW Packet Gateway-   PHICH Physical Hybrid-ARQ Indicator Channel-   PLMN Public Land Mobile Network-   PMI Precoder Matrix Indicator-   PRACH Physical Random Access Channel-   PRS Positioning Reference Signal-   PSS Primary Synchronization Signal-   PUCCH Physical Uplink Control Channel-   PUSCH Physical Uplink Shared Channel-   RACH Random Access Channel-   QAM Quadrature Amplitude Modulation-   RAN Radio Access Network-   RAT Radio Access Technology-   RLM Radio Link Management-   RNC Radio Network Controller-   RNTI Radio Network Temporary Identifier-   RRC Radio Resource Control-   RRM Radio Resource Management-   RS Reference Signal-   RSCP Received Signal Code Power-   RSRP Reference Symbol Received Power OR Reference Signal Received    Power-   RSRQ Reference Signal Received Quality OR Reference Symbol Received    Quality-   RSSI Received Signal Strength Indicator-   RSTD Reference Signal Time Difference-   SCH Synchronization Channel-   SCell Secondary Cell-   SDU Service Data Unit-   SFN System Frame Number-   SGW Serving Gateway-   SI System Information-   SIB System Information Block-   SNR Signal to Noise Ratio-   SON Self Optimized Network-   SS Synchronization Signal-   SSS Secondary Synchronization Signal-   TDD Time Division Duplex-   TDOA Time Difference of Arrival-   TOA Time of Arrival-   TSS Tertiary Synchronization Signal-   TTI Transmission Time Interval-   UE User Equipment-   UL Uplink-   UMTS Universal Mobile Telecommunication System-   USIM Universal Subscriber Identity Module-   UTDOA Uplink Time Difference of Arrival-   UTRA Universal Terrestrial Radio Access-   UTRAN Universal Terrestrial Radio Access Network-   WCDMA Wide CDMA-   WLAN Wide Local Area Network

1. A method by a wireless device, the method comprising: receiving, froma source network node, a handover command, the handover commandcomprising a plurality of suitability thresholds, wherein the pluralityof suitability thresholds comprises a first suitability threshold and asecond suitability threshold; performing, by the wireless device, atleast one measurement of each of a plurality of beams detected by thewireless device; comparing at least one measurement of the plurality ofbeams to the first suitability threshold; selecting a first beam of theplurality of beams based on the comparison; and transmitting a firstpreamble associated with a random access procedure, the first preambletransmitted using the selected first beam; upon not receiving a randomaccess response to the first preamble transmission: comparing at leastone measurement of the plurality of beams to the second suitabilitythreshold; selecting a second beam of the plurality of beams based onthe comparison; and transmitting a second preamble associated with therandom access procedure, the second preamble transmitted using theselected second beam.
 2. The method of claim 1, wherein the handovercommand is generated by a target network node that is performing ahandover of the wireless device from the source network node to thetarget network node.
 3. The method of claim 1, wherein: the plurality ofsuitability thresholds comprise a plurality of minimum radio qualityvalues, comparing at least one measurement of the plurality of beamscomprises comparing at least one measurement for each of the pluralityof beams to at least one of the plurality of minimum radio qualityvalues, and selecting the first beam comprises selecting a particularbeam that has an associated measurement that is greater than the atleast one minimum radio quality.
 4. The method of claim 1, wherein eachof the plurality of suitability thresholds is associated with adifferent one of a plurality of reference signals.
 5. The method ofclaim 1, wherein: the first suitability threshold is associated withcontention based random access (CBRA), and the second suitabilitythreshold is associated with contention free random access (CFRA). 6.The method of claim 1, wherein: the first suitability threshold is for asynchronization signal block (SSB), and the second suitability thresholdis for a channel state information-reference signal (CSI-RS).
 7. Awireless device comprising: an interface configured to receive, from asource network node, a handover command, the handover command comprisinga plurality of suitability thresholds, wherein the plurality ofsuitability thresholds comprises a first suitability threshold and asecond suitability threshold; and processing circuitry configured to:perform at least one measurement of each of a plurality of beamsdetected by the wireless device; compare at least one measurement of theplurality of beams to the first suitability threshold; and select aparticular beam of the plurality of beams based on the comparison;wherein the interface is further configured to transmit a first preambleassociated with a random access procedure, the first preambletransmitted using the selected first beam; upon the interface notreceiving a random access response to the first preamble transmission:the processing circuitry is further configured to: compare at least onemeasurement of the plurality of beams to the second suitabilitythreshold; and select a second beam of the plurality of beams based onthe comparison; and the interface is further configured to transmit asecond preamble associated with the random access procedure, the secondpreamble transmitted using the selected second beam.
 8. The wirelessdevice of claim 7, wherein the handover command is generated by a targetnetwork node that is performing a handover of the wireless device fromthe source network node to the target network node.
 9. The wirelessdevice of claim 7, wherein: the plurality of suitability thresholdscomprises a plurality of minimum radio quality values, the processingcircuitry configured to compare at least one measurement for each of theplurality of beams comprises processing circuitry configured to compareat least one measurement for each of the plurality of beams to at leastone of the plurality of minimum radio quality values, and the processingcircuitry configured to select the first beam comprises processingcircuitry configured to select a particular beam that has an associatedmeasurement that is greater than the at least one minimum radio quality.10. The wireless device of claim 7, wherein each of the plurality ofsuitability thresholds is associated with a different one of a pluralityof reference signals.
 11. The wireless device of claim 7, wherein: thefirst suitability threshold is associated with contention based randomaccess (CBRA), and the second suitability threshold is associated withcontention free random access (CFRA).
 12. The wireless device of claim7, wherein: the first suitability threshold is for a synchronizationsignal block (SSB), and the second suitability threshold is for achannel state information-reference signal (CSI-RS).